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@angular/compiler

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Angular - the compiler library

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/** * @license * Copyright Google LLC All Rights Reserved. * * Use of this source code is governed by an MIT-style license that can be * found in the LICENSE file at https://angular.io/license */ import * as chars from '../chars'; import { DEFAULT_INTERPOLATION_CONFIG } from '../ml_parser/interpolation_config'; import { AbsoluteSourceSpan, ASTWithSource, Binary, BindingPipe, Call, Chain, Conditional, EmptyExpr, ExpressionBinding, ImplicitReceiver, Interpolation, KeyedRead, KeyedWrite, LiteralArray, LiteralMap, LiteralPrimitive, NonNullAssert, ParserError, ParseSpan, PrefixNot, PropertyRead, PropertyWrite, Quote, RecursiveAstVisitor, SafeKeyedRead, SafePropertyRead, ThisReceiver, Unary, VariableBinding } from './ast'; import { EOF, isIdentifier, TokenType } from './lexer'; export class SplitInterpolation { constructor(strings, expressions, offsets) { this.strings = strings; this.expressions = expressions; this.offsets = offsets; } } export class TemplateBindingParseResult { constructor(templateBindings, warnings, errors) { this.templateBindings = templateBindings; this.warnings = warnings; this.errors = errors; } } export class Parser { constructor(_lexer) { this._lexer = _lexer; this.errors = []; this.simpleExpressionChecker = SimpleExpressionChecker; } parseAction(input, location, absoluteOffset, interpolationConfig = DEFAULT_INTERPOLATION_CONFIG) { this._checkNoInterpolation(input, location, interpolationConfig); const sourceToLex = this._stripComments(input); const tokens = this._lexer.tokenize(this._stripComments(input)); const ast = new _ParseAST(input, location, absoluteOffset, tokens, sourceToLex.length, true, this.errors, input.length - sourceToLex.length) .parseChain(); return new ASTWithSource(ast, input, location, absoluteOffset, this.errors); } parseBinding(input, location, absoluteOffset, interpolationConfig = DEFAULT_INTERPOLATION_CONFIG) { const ast = this._parseBindingAst(input, location, absoluteOffset, interpolationConfig); return new ASTWithSource(ast, input, location, absoluteOffset, this.errors); } checkSimpleExpression(ast) { const checker = new this.simpleExpressionChecker(); ast.visit(checker); return checker.errors; } parseSimpleBinding(input, location, absoluteOffset, interpolationConfig = DEFAULT_INTERPOLATION_CONFIG) { const ast = this._parseBindingAst(input, location, absoluteOffset, interpolationConfig); const errors = this.checkSimpleExpression(ast); if (errors.length > 0) { this._reportError(`Host binding expression cannot contain ${errors.join(' ')}`, input, location); } return new ASTWithSource(ast, input, location, absoluteOffset, this.errors); } _reportError(message, input, errLocation, ctxLocation) { this.errors.push(new ParserError(message, input, errLocation, ctxLocation)); } _parseBindingAst(input, location, absoluteOffset, interpolationConfig) { // Quotes expressions use 3rd-party expression language. We don't want to use // our lexer or parser for that, so we check for that ahead of time. const quote = this._parseQuote(input, location, absoluteOffset); if (quote != null) { return quote; } this._checkNoInterpolation(input, location, interpolationConfig); const sourceToLex = this._stripComments(input); const tokens = this._lexer.tokenize(sourceToLex); return new _ParseAST(input, location, absoluteOffset, tokens, sourceToLex.length, false, this.errors, input.length - sourceToLex.length) .parseChain(); } _parseQuote(input, location, absoluteOffset) { if (input == null) return null; const prefixSeparatorIndex = input.indexOf(':'); if (prefixSeparatorIndex == -1) return null; const prefix = input.substring(0, prefixSeparatorIndex).trim(); if (!isIdentifier(prefix)) return null; const uninterpretedExpression = input.substring(prefixSeparatorIndex + 1); const span = new ParseSpan(0, input.length); return new Quote(span, span.toAbsolute(absoluteOffset), prefix, uninterpretedExpression, location); } /** * Parse microsyntax template expression and return a list of bindings or * parsing errors in case the given expression is invalid. * * For example, * ``` * <div *ngFor="let item of items"> * ^ ^ absoluteValueOffset for `templateValue` * absoluteKeyOffset for `templateKey` * ``` * contains three bindings: * 1. ngFor -> null * 2. item -> NgForOfContext.$implicit * 3. ngForOf -> items * * This is apparent from the de-sugared template: * ``` * <ng-template ngFor let-item [ngForOf]="items"> * ``` * * @param templateKey name of directive, without the * prefix. For example: ngIf, ngFor * @param templateValue RHS of the microsyntax attribute * @param templateUrl template filename if it's external, component filename if it's inline * @param absoluteKeyOffset start of the `templateKey` * @param absoluteValueOffset start of the `templateValue` */ parseTemplateBindings(templateKey, templateValue, templateUrl, absoluteKeyOffset, absoluteValueOffset) { const tokens = this._lexer.tokenize(templateValue); const parser = new _ParseAST(templateValue, templateUrl, absoluteValueOffset, tokens, templateValue.length, false /* parseAction */, this.errors, 0 /* relative offset */); return parser.parseTemplateBindings({ source: templateKey, span: new AbsoluteSourceSpan(absoluteKeyOffset, absoluteKeyOffset + templateKey.length), }); } parseInterpolation(input, location, absoluteOffset, interpolationConfig = DEFAULT_INTERPOLATION_CONFIG) { const { strings, expressions, offsets } = this.splitInterpolation(input, location, interpolationConfig); if (expressions.length === 0) return null; const expressionNodes = []; for (let i = 0; i < expressions.length; ++i) { const expressionText = expressions[i].text; const sourceToLex = this._stripComments(expressionText); const tokens = this._lexer.tokenize(sourceToLex); const ast = new _ParseAST(input, location, absoluteOffset, tokens, sourceToLex.length, false, this.errors, offsets[i] + (expressionText.length - sourceToLex.length)) .parseChain(); expressionNodes.push(ast); } return this.createInterpolationAst(strings.map(s => s.text), expressionNodes, input, location, absoluteOffset); } /** * Similar to `parseInterpolation`, but treats the provided string as a single expression * element that would normally appear within the interpolation prefix and suffix (`{{` and `}}`). * This is used for parsing the switch expression in ICUs. */ parseInterpolationExpression(expression, location, absoluteOffset) { const sourceToLex = this._stripComments(expression); const tokens = this._lexer.tokenize(sourceToLex); const ast = new _ParseAST(expression, location, absoluteOffset, tokens, sourceToLex.length, /* parseAction */ false, this.errors, 0) .parseChain(); const strings = ['', '']; // The prefix and suffix strings are both empty return this.createInterpolationAst(strings, [ast], expression, location, absoluteOffset); } createInterpolationAst(strings, expressions, input, location, absoluteOffset) { const span = new ParseSpan(0, input.length); const interpolation = new Interpolation(span, span.toAbsolute(absoluteOffset), strings, expressions); return new ASTWithSource(interpolation, input, location, absoluteOffset, this.errors); } /** * Splits a string of text into "raw" text segments and expressions present in interpolations in * the string. * Returns `null` if there are no interpolations, otherwise a * `SplitInterpolation` with splits that look like * <raw text> <expression> <raw text> ... <raw text> <expression> <raw text> */ splitInterpolation(input, location, interpolationConfig = DEFAULT_INTERPOLATION_CONFIG) { const strings = []; const expressions = []; const offsets = []; let i = 0; let atInterpolation = false; let extendLastString = false; let { start: interpStart, end: interpEnd } = interpolationConfig; while (i < input.length) { if (!atInterpolation) { // parse until starting {{ const start = i; i = input.indexOf(interpStart, i); if (i === -1) { i = input.length; } const text = input.substring(start, i); strings.push({ text, start, end: i }); atInterpolation = true; } else { // parse from starting {{ to ending }} while ignoring content inside quotes. const fullStart = i; const exprStart = fullStart + interpStart.length; const exprEnd = this._getInterpolationEndIndex(input, interpEnd, exprStart); if (exprEnd === -1) { // Could not find the end of the interpolation; do not parse an expression. // Instead we should extend the content on the last raw string. atInterpolation = false; extendLastString = true; break; } const fullEnd = exprEnd + interpEnd.length; const text = input.substring(exprStart, exprEnd); if (text.trim().length === 0) { this._reportError('Blank expressions are not allowed in interpolated strings', input, `at column ${i} in`, location); } expressions.push({ text, start: fullStart, end: fullEnd }); offsets.push(exprStart); i = fullEnd; atInterpolation = false; } } if (!atInterpolation) { // If we are now at a text section, add the remaining content as a raw string. if (extendLastString) { const piece = strings[strings.length - 1]; piece.text += input.substring(i); piece.end = input.length; } else { strings.push({ text: input.substring(i), start: i, end: input.length }); } } return new SplitInterpolation(strings, expressions, offsets); } wrapLiteralPrimitive(input, location, absoluteOffset) { const span = new ParseSpan(0, input == null ? 0 : input.length); return new ASTWithSource(new LiteralPrimitive(span, span.toAbsolute(absoluteOffset), input), input, location, absoluteOffset, this.errors); } _stripComments(input) { const i = this._commentStart(input); return i != null ? input.substring(0, i).trim() : input; } _commentStart(input) { let outerQuote = null; for (let i = 0; i < input.length - 1; i++) { const char = input.charCodeAt(i); const nextChar = input.charCodeAt(i + 1); if (char === chars.$SLASH && nextChar == chars.$SLASH && outerQuote == null) return i; if (outerQuote === char) { outerQuote = null; } else if (outerQuote == null && chars.isQuote(char)) { outerQuote = char; } } return null; } _checkNoInterpolation(input, location, { start, end }) { let startIndex = -1; let endIndex = -1; for (const charIndex of this._forEachUnquotedChar(input, 0)) { if (startIndex === -1) { if (input.startsWith(start)) { startIndex = charIndex; } } else { endIndex = this._getInterpolationEndIndex(input, end, charIndex); if (endIndex > -1) { break; } } } if (startIndex > -1 && endIndex > -1) { this._reportError(`Got interpolation (${start}${end}) where expression was expected`, input, `at column ${startIndex} in`, location); } } /** * Finds the index of the end of an interpolation expression * while ignoring comments and quoted content. */ _getInterpolationEndIndex(input, expressionEnd, start) { for (const charIndex of this._forEachUnquotedChar(input, start)) { if (input.startsWith(expressionEnd, charIndex)) { return charIndex; } // Nothing else in the expression matters after we've // hit a comment so look directly for the end token. if (input.startsWith('//', charIndex)) { return input.indexOf(expressionEnd, charIndex); } } return -1; } /** * Generator used to iterate over the character indexes of a string that are outside of quotes. * @param input String to loop through. * @param start Index within the string at which to start. */ *_forEachUnquotedChar(input, start) { let currentQuote = null; let escapeCount = 0; for (let i = start; i < input.length; i++) { const char = input[i]; // Skip the characters inside quotes. Note that we only care about the outer-most // quotes matching up and we need to account for escape characters. if (chars.isQuote(input.charCodeAt(i)) && (currentQuote === null || currentQuote === char) && escapeCount % 2 === 0) { currentQuote = currentQuote === null ? char : null; } else if (currentQuote === null) { yield i; } escapeCount = char === '\\' ? escapeCount + 1 : 0; } } } export class IvyParser extends Parser { constructor() { super(...arguments); this.simpleExpressionChecker = IvySimpleExpressionChecker; } } /** Describes a stateful context an expression parser is in. */ var ParseContextFlags; (function (ParseContextFlags) { ParseContextFlags[ParseContextFlags["None"] = 0] = "None"; /** * A Writable context is one in which a value may be written to an lvalue. * For example, after we see a property access, we may expect a write to the * property via the "=" operator. * prop * ^ possible "=" after */ ParseContextFlags[ParseContextFlags["Writable"] = 1] = "Writable"; })(ParseContextFlags || (ParseContextFlags = {})); export class _ParseAST { constructor(input, location, absoluteOffset, tokens, inputLength, parseAction, errors, offset) { this.input = input; this.location = location; this.absoluteOffset = absoluteOffset; this.tokens = tokens; this.inputLength = inputLength; this.parseAction = parseAction; this.errors = errors; this.offset = offset; this.rparensExpected = 0; this.rbracketsExpected = 0; this.rbracesExpected = 0; this.context = ParseContextFlags.None; // Cache of expression start and input indeces to the absolute source span they map to, used to // prevent creating superfluous source spans in `sourceSpan`. // A serial of the expression start and input index is used for mapping because both are stateful // and may change for subsequent expressions visited by the parser. this.sourceSpanCache = new Map(); this.index = 0; } peek(offset) { const i = this.index + offset; return i < this.tokens.length ? this.tokens[i] : EOF; } get next() { return this.peek(0); } /** Whether all the parser input has been processed. */ get atEOF() { return this.index >= this.tokens.length; } /** * Index of the next token to be processed, or the end of the last token if all have been * processed. */ get inputIndex() { return this.atEOF ? this.currentEndIndex : this.next.index + this.offset; } /** * End index of the last processed token, or the start of the first token if none have been * processed. */ get currentEndIndex() { if (this.index > 0) { const curToken = this.peek(-1); return curToken.end + this.offset; } // No tokens have been processed yet; return the next token's start or the length of the input // if there is no token. if (this.tokens.length === 0) { return this.inputLength + this.offset; } return this.next.index + this.offset; } /** * Returns the absolute offset of the start of the current token. */ get currentAbsoluteOffset() { return this.absoluteOffset + this.inputIndex; } /** * Retrieve a `ParseSpan` from `start` to the current position (or to `artificialEndIndex` if * provided). * * @param start Position from which the `ParseSpan` will start. * @param artificialEndIndex Optional ending index to be used if provided (and if greater than the * natural ending index) */ span(start, artificialEndIndex) { let endIndex = this.currentEndIndex; if (artificialEndIndex !== undefined && artificialEndIndex > this.currentEndIndex) { endIndex = artificialEndIndex; } // In some unusual parsing scenarios (like when certain tokens are missing and an `EmptyExpr` is // being created), the current token may already be advanced beyond the `currentEndIndex`. This // appears to be a deep-seated parser bug. // // As a workaround for now, swap the start and end indices to ensure a valid `ParseSpan`. // TODO(alxhub): fix the bug upstream in the parser state, and remove this workaround. if (start > endIndex) { const tmp = endIndex; endIndex = start; start = tmp; } return new ParseSpan(start, endIndex); } sourceSpan(start, artificialEndIndex) { const serial = `${start}@${this.inputIndex}:${artificialEndIndex}`; if (!this.sourceSpanCache.has(serial)) { this.sourceSpanCache.set(serial, this.span(start, artificialEndIndex).toAbsolute(this.absoluteOffset)); } return this.sourceSpanCache.get(serial); } advance() { this.index++; } /** * Executes a callback in the provided context. */ withContext(context, cb) { this.context |= context; const ret = cb(); this.context ^= context; return ret; } consumeOptionalCharacter(code) { if (this.next.isCharacter(code)) { this.advance(); return true; } else { return false; } } peekKeywordLet() { return this.next.isKeywordLet(); } peekKeywordAs() { return this.next.isKeywordAs(); } /** * Consumes an expected character, otherwise emits an error about the missing expected character * and skips over the token stream until reaching a recoverable point. * * See `this.error` and `this.skip` for more details. */ expectCharacter(code) { if (this.consumeOptionalCharacter(code)) return; this.error(`Missing expected ${String.fromCharCode(code)}`); } consumeOptionalOperator(op) { if (this.next.isOperator(op)) { this.advance(); return true; } else { return false; } } expectOperator(operator) { if (this.consumeOptionalOperator(operator)) return; this.error(`Missing expected operator ${operator}`); } prettyPrintToken(tok) { return tok === EOF ? 'end of input' : `token ${tok}`; } expectIdentifierOrKeyword() { const n = this.next; if (!n.isIdentifier() && !n.isKeyword()) { if (n.isPrivateIdentifier()) { this._reportErrorForPrivateIdentifier(n, 'expected identifier or keyword'); } else { this.error(`Unexpected ${this.prettyPrintToken(n)}, expected identifier or keyword`); } return null; } this.advance(); return n.toString(); } expectIdentifierOrKeywordOrString() { const n = this.next; if (!n.isIdentifier() && !n.isKeyword() && !n.isString()) { if (n.isPrivateIdentifier()) { this._reportErrorForPrivateIdentifier(n, 'expected identifier, keyword or string'); } else { this.error(`Unexpected ${this.prettyPrintToken(n)}, expected identifier, keyword, or string`); } return ''; } this.advance(); return n.toString(); } parseChain() { const exprs = []; const start = this.inputIndex; while (this.index < this.tokens.length) { const expr = this.parsePipe(); exprs.push(expr); if (this.consumeOptionalCharacter(chars.$SEMICOLON)) { if (!this.parseAction) { this.error('Binding expression cannot contain chained expression'); } while (this.consumeOptionalCharacter(chars.$SEMICOLON)) { } // read all semicolons } else if (this.index < this.tokens.length) { this.error(`Unexpected token '${this.next}'`); } } if (exprs.length == 0) { // We have no expressions so create an empty expression that spans the entire input length const artificialStart = this.offset; const artificialEnd = this.offset + this.inputLength; return new EmptyExpr(this.span(artificialStart, artificialEnd), this.sourceSpan(artificialStart, artificialEnd)); } if (exprs.length == 1) return exprs[0]; return new Chain(this.span(start), this.sourceSpan(start), exprs); } parsePipe() { const start = this.inputIndex; let result = this.parseExpression(); if (this.consumeOptionalOperator('|')) { if (this.parseAction) { this.error('Cannot have a pipe in an action expression'); } do { const nameStart = this.inputIndex; let nameId = this.expectIdentifierOrKeyword(); let nameSpan; let fullSpanEnd = undefined; if (nameId !== null) { nameSpan = this.sourceSpan(nameStart); } else { // No valid identifier was found, so we'll assume an empty pipe name (''). nameId = ''; // However, there may have been whitespace present between the pipe character and the next // token in the sequence (or the end of input). We want to track this whitespace so that // the `BindingPipe` we produce covers not just the pipe character, but any trailing // whitespace beyond it. Another way of thinking about this is that the zero-length name // is assumed to be at the end of any whitespace beyond the pipe character. // // Therefore, we push the end of the `ParseSpan` for this pipe all the way up to the // beginning of the next token, or until the end of input if the next token is EOF. fullSpanEnd = this.next.index !== -1 ? this.next.index : this.inputLength + this.offset; // The `nameSpan` for an empty pipe name is zero-length at the end of any whitespace // beyond the pipe character. nameSpan = new ParseSpan(fullSpanEnd, fullSpanEnd).toAbsolute(this.absoluteOffset); } const args = []; while (this.consumeOptionalCharacter(chars.$COLON)) { args.push(this.parseExpression()); // If there are additional expressions beyond the name, then the artificial end for the // name is no longer relevant. } result = new BindingPipe(this.span(start), this.sourceSpan(start, fullSpanEnd), result, nameId, args, nameSpan); } while (this.consumeOptionalOperator('|')); } return result; } parseExpression() { return this.parseConditional(); } parseConditional() { const start = this.inputIndex; const result = this.parseLogicalOr(); if (this.consumeOptionalOperator('?')) { const yes = this.parsePipe(); let no; if (!this.consumeOptionalCharacter(chars.$COLON)) { const end = this.inputIndex; const expression = this.input.substring(start, end); this.error(`Conditional expression ${expression} requires all 3 expressions`); no = new EmptyExpr(this.span(start), this.sourceSpan(start)); } else { no = this.parsePipe(); } return new Conditional(this.span(start), this.sourceSpan(start), result, yes, no); } else { return result; } } parseLogicalOr() { // '||' const start = this.inputIndex; let result = this.parseLogicalAnd(); while (this.consumeOptionalOperator('||')) { const right = this.parseLogicalAnd(); result = new Binary(this.span(start), this.sourceSpan(start), '||', result, right); } return result; } parseLogicalAnd() { // '&&' const start = this.inputIndex; let result = this.parseNullishCoalescing(); while (this.consumeOptionalOperator('&&')) { const right = this.parseNullishCoalescing(); result = new Binary(this.span(start), this.sourceSpan(start), '&&', result, right); } return result; } parseNullishCoalescing() { // '??' const start = this.inputIndex; let result = this.parseEquality(); while (this.consumeOptionalOperator('??')) { const right = this.parseEquality(); result = new Binary(this.span(start), this.sourceSpan(start), '??', result, right); } return result; } parseEquality() { // '==','!=','===','!==' const start = this.inputIndex; let result = this.parseRelational(); while (this.next.type == TokenType.Operator) { const operator = this.next.strValue; switch (operator) { case '==': case '===': case '!=': case '!==': this.advance(); const right = this.parseRelational(); result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right); continue; } break; } return result; } parseRelational() { // '<', '>', '<=', '>=' const start = this.inputIndex; let result = this.parseAdditive(); while (this.next.type == TokenType.Operator) { const operator = this.next.strValue; switch (operator) { case '<': case '>': case '<=': case '>=': this.advance(); const right = this.parseAdditive(); result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right); continue; } break; } return result; } parseAdditive() { // '+', '-' const start = this.inputIndex; let result = this.parseMultiplicative(); while (this.next.type == TokenType.Operator) { const operator = this.next.strValue; switch (operator) { case '+': case '-': this.advance(); let right = this.parseMultiplicative(); result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right); continue; } break; } return result; } parseMultiplicative() { // '*', '%', '/' const start = this.inputIndex; let result = this.parsePrefix(); while (this.next.type == TokenType.Operator) { const operator = this.next.strValue; switch (operator) { case '*': case '%': case '/': this.advance(); let right = this.parsePrefix(); result = new Binary(this.span(start), this.sourceSpan(start), operator, result, right); continue; } break; } return result; } parsePrefix() { if (this.next.type == TokenType.Operator) { const start = this.inputIndex; const operator = this.next.strValue; let result; switch (operator) { case '+': this.advance(); result = this.parsePrefix(); return Unary.createPlus(this.span(start), this.sourceSpan(start), result); case '-': this.advance(); result = this.parsePrefix(); return Unary.createMinus(this.span(start), this.sourceSpan(start), result); case '!': this.advance(); result = this.parsePrefix(); return new PrefixNot(this.span(start), this.sourceSpan(start), result); } } return this.parseCallChain(); } parseCallChain() { const start = this.inputIndex; let result = this.parsePrimary(); while (true) { if (this.consumeOptionalCharacter(chars.$PERIOD)) { result = this.parseAccessMemberOrCall(result, start, false); } else if (this.consumeOptionalOperator('?.')) { result = this.consumeOptionalCharacter(chars.$LBRACKET) ? this.parseKeyedReadOrWrite(result, start, true) : this.parseAccessMemberOrCall(result, start, true); } else if (this.consumeOptionalCharacter(chars.$LBRACKET)) { result = this.parseKeyedReadOrWrite(result, start, false); } else if (this.consumeOptionalCharacter(chars.$LPAREN)) { const argumentStart = this.inputIndex; this.rparensExpected++; const args = this.parseCallArguments(); const argumentSpan = this.span(argumentStart, this.inputIndex).toAbsolute(this.absoluteOffset); this.rparensExpected--; this.expectCharacter(chars.$RPAREN); result = new Call(this.span(start), this.sourceSpan(start), result, args, argumentSpan); } else if (this.consumeOptionalOperator('!')) { result = new NonNullAssert(this.span(start), this.sourceSpan(start), result); } else { return result; } } } parsePrimary() { const start = this.inputIndex; if (this.consumeOptionalCharacter(chars.$LPAREN)) { this.rparensExpected++; const result = this.parsePipe(); this.rparensExpected--; this.expectCharacter(chars.$RPAREN); return result; } else if (this.next.isKeywordNull()) { this.advance(); return new LiteralPrimitive(this.span(start), this.sourceSpan(start), null); } else if (this.next.isKeywordUndefined()) { this.advance(); return new LiteralPrimitive(this.span(start), this.sourceSpan(start), void 0); } else if (this.next.isKeywordTrue()) { this.advance(); return new LiteralPrimitive(this.span(start), this.sourceSpan(start), true); } else if (this.next.isKeywordFalse()) { this.advance(); return new LiteralPrimitive(this.span(start), this.sourceSpan(start), false); } else if (this.next.isKeywordThis()) { this.advance(); return new ThisReceiver(this.span(start), this.sourceSpan(start)); } else if (this.consumeOptionalCharacter(chars.$LBRACKET)) { this.rbracketsExpected++; const elements = this.parseExpressionList(chars.$RBRACKET); this.rbracketsExpected--; this.expectCharacter(chars.$RBRACKET); return new LiteralArray(this.span(start), this.sourceSpan(start), elements); } else if (this.next.isCharacter(chars.$LBRACE)) { return this.parseLiteralMap(); } else if (this.next.isIdentifier()) { return this.parseAccessMemberOrCall(new ImplicitReceiver(this.span(start), this.sourceSpan(start)), start, false); } else if (this.next.isNumber()) { const value = this.next.toNumber(); this.advance(); return new LiteralPrimitive(this.span(start), this.sourceSpan(start), value); } else if (this.next.isString()) { const literalValue = this.next.toString(); this.advance(); return new LiteralPrimitive(this.span(start), this.sourceSpan(start), literalValue); } else if (this.next.isPrivateIdentifier()) { this._reportErrorForPrivateIdentifier(this.next, null); return new EmptyExpr(this.span(start), this.sourceSpan(start)); } else if (this.index >= this.tokens.length) { this.error(`Unexpected end of expression: ${this.input}`); return new EmptyExpr(this.span(start), this.sourceSpan(start)); } else { this.error(`Unexpected token ${this.next}`); return new EmptyExpr(this.span(start), this.sourceSpan(start)); } } parseExpressionList(terminator) { const result = []; do { if (!this.next.isCharacter(terminator)) { result.push(this.parsePipe()); } else { break; } } while (this.consumeOptionalCharacter(chars.$COMMA)); return result; } parseLiteralMap() { const keys = []; const values = []; const start = this.inputIndex; this.expectCharacter(chars.$LBRACE); if (!this.consumeOptionalCharacter(chars.$RBRACE)) { this.rbracesExpected++; do { const keyStart = this.inputIndex; const quoted = this.next.isString(); const key = this.expectIdentifierOrKeywordOrString(); keys.push({ key, quoted }); // Properties with quoted keys can't use the shorthand syntax. if (quoted) { this.expectCharacter(chars.$COLON); values.push(this.parsePipe()); } else if (this.consumeOptionalCharacter(chars.$COLON)) { values.push(this.parsePipe()); } else { const span = this.span(keyStart); const sourceSpan = this.sourceSpan(keyStart); values.push(new PropertyRead(span, sourceSpan, sourceSpan, new ImplicitReceiver(span, sourceSpan), key)); } } while (this.consumeOptionalCharacter(chars.$COMMA)); this.rbracesExpected--; this.expectCharacter(chars.$RBRACE); } return new LiteralMap(this.span(start), this.sourceSpan(start), keys, values); } parseAccessMemberOrCall(readReceiver, start, isSafe) { const nameStart = this.inputIndex; const id = this.withContext(ParseContextFlags.Writable, () => { const id = this.expectIdentifierOrKeyword() ?? ''; if (id.length === 0) { this.error(`Expected identifier for property access`, readReceiver.span.end); } return id; }); const nameSpan = this.sourceSpan(nameStart); let receiver; if (isSafe) { if (this.consumeOptionalOperator('=')) { this.error('The \'?.\' operator cannot be used in the assignment'); receiver = new EmptyExpr(this.span(start), this.sourceSpan(start)); } else { receiver = new SafePropertyRead(this.span(start), this.sourceSpan(start), nameSpan, readReceiver, id); } } else { if (this.consumeOptionalOperator('=')) { if (!this.parseAction) { this.error('Bindings cannot contain assignments'); return new EmptyExpr(this.span(start), this.sourceSpan(start)); } const value = this.parseConditional(); receiver = new PropertyWrite(this.span(start), this.sourceSpan(start), nameSpan, readReceiver, id, value); } else { receiver = new PropertyRead(this.span(start), this.sourceSpan(start), nameSpan, readReceiver, id); } } if (this.consumeOptionalCharacter(chars.$LPAREN)) { const argumentStart = this.inputIndex; this.rparensExpected++; const args = this.parseCallArguments(); const argumentSpan = this.span(argumentStart, this.inputIndex).toAbsolute(this.absoluteOffset); this.expectCharacter(chars.$RPAREN); this.rparensExpected--; const span = this.span(start); const sourceSpan = this.sourceSpan(start); return new Call(span, sourceSpan, receiver, args, argumentSpan); } return receiver; } parseCallArguments() { if (this.next.isCharacter(chars.$RPAREN)) return []; const positionals = []; do { positionals.push(this.parsePipe()); } while (this.consumeOptionalCharacter(chars.$COMMA)); return positionals; } /** * Parses an identifier, a keyword, a string with an optional `-` in between, * and returns the string along with its absolute source span. */ expectTemplateBindingKey() { let result = ''; let operatorFound = false; const start = this.currentAbsoluteOffset; do { result += this.expectIdentifierOrKeywordOrString(); operatorFound = this.consumeOptionalOperator('-'); if (operatorFound) { result += '-'; } } while (operatorFound); return { source: result, span: new AbsoluteSourceSpan(start, start + result.length), }; } /** * Parse microsyntax template expression and return a list of bindings or * parsing errors in case the given expression is invalid. * * For example, * ``` * <div *ngFor="let item of items; index as i; trackBy: func"> * ``` * contains five bindings: * 1. ngFor -> null * 2. item -> NgForOfContext.$implicit * 3. ngForOf -> items * 4. i -> NgForOfContext.index * 5. ngForTrackBy -> func * * For a full description of the microsyntax grammar, see * https://gist.github.com/mhevery/d3530294cff2e4a1b3fe15ff75d08855 * * @param templateKey name of the microsyntax directive, like ngIf, ngFor, * without the *, along with its absolute span. */ parseTemplateBindings(templateKey) { const bindings = []; // The first binding is for the template key itself // In *ngFor="let item of items", key = "ngFor", value = null // In *ngIf="cond | pipe", key = "ngIf", value = "cond | pipe" bindings.push(...this.parseDirectiveKeywordBindings(templateKey)); while (this.index < this.tokens.length) { // If it starts with 'let', then this must be variable declaration const letBinding = this.parseLetBinding(); if (letBinding) { bindings.push(letBinding); } else { // Two possible cases here, either `value "as" key` or // "directive-keyword expression". We don't know which case, but both // "value" and "directive-keyword" are template binding key, so consume // the key first. const key = this.expectTemplateBindingKey(); // Peek at the next token, if it is "as" then this must be variable // declaration. const binding = this.parseAsBinding(key); if (binding) { bindings.push(binding); } else { // Otherwise the key must be a directive keyword, like "of". Transform // the key to actual key. Eg. of -> ngForOf, trackBy -> ngForTrackBy key.source = templateKey.source + key.source.charAt(0).toUpperCase() + key.source.substring(1); bindings.push(...this.parseDirectiveKeywordBindings(key)); } } this.consumeStatementTerminator(); } return new TemplateBindingParseResult(bindings, [] /* warnings */, this.errors); } parseKeyedReadOrWrite(receiver, start, isSafe) { return this.withContext(ParseContextFlags.Writable, () => { this.rbracketsExpected++; const key = this.parsePipe(); if (key instanceof EmptyExpr) { this.error(`Key access cannot be empty`); } this.rbracketsExpected--; this.expectCharacter(chars.$RBRACKET); if (this.consumeOptionalOperator('=')) { if (isSafe) { this.error('The \'?.\' operator cannot be used in the assignment'); } else { const value = this.parseConditional(); return new KeyedWrite(this.span(start), this.sourceSpan(start), receiver, key, value); } } else { return isSafe ? new SafeKeyedRead(this.span(start), this.sourceSpan(start), receiver, key) : new KeyedRead(this.span(start), this.sourceSpan(start), receiver, key); } return new EmptyExpr(this.span(start), this.sourceSpan(start)); }); } /** * Parse a directive keyword, followed by a mandatory expression. * For example, "of items", "trackBy: func". * The bindings are: ngForOf -> items, ngForTrackBy -> func * There could be an optional "as" binding that follows the expression. * For example, * ``` * *ngFor="let item of items | slice:0:1 as collection". * ^^ ^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^ * keyword bound target optional 'as' binding * ``` * * @param key binding key, for example, ngFor, ngIf, ngForOf, along with its * absolute span. */ parseDirectiveKeywordBindings(key) { const bindings = []; this.consumeOptionalCharacter(chars.$COLON); // trackBy: trackByFunction const value = this.getDirectiveBoundTarget(); let spanEnd = this.currentAbsoluteOffset; // The binding could optionally be followed by "as". For example, // *ngIf="cond | pipe as x". In this case, the key in the "as" binding // is "x" and the value is the template key itself ("ngIf"). Note that the // 'key' in the current context now becomes the "value" in the next binding. const asBinding = this.parseAsBinding(key); if (!asBinding) { this.consumeStatementTerminator(); spanEnd = this.currentAbsoluteOffset; } const sourceSpan = new AbsoluteSourceSpan(key.span.start, spanEnd); bindings.push(new ExpressionBinding(sourceSpan, key, value)); if (asBinding) { bindings.push(asBinding); } return bindings; } /** * Return the expression AST for the bound target of a directive keyword * binding. For example, * ``` * *ngIf="condition | pipe" * ^^^^^^^^^^^^^^^^ bound target for "ngIf" * *ngFor="let item of items" * ^^^^^ bound target for "ngForOf" * ``` */ getDirectiveBoundTarget() { if (this.next === EOF || this.peekKeywordAs() || this.peekKeywordLet()) { return null; } const ast = this.parsePipe(); // example: "condition | async" const { start, end } = ast.span; const value = this.input.substring(start, end); return new ASTWithSource(ast, value, this.location, this.absoluteOffset + start, this.errors); } /** * Return the binding for a variable declared using `as`. Note that the order * of the key-value pair in this declaration is reversed. For example, * ``` * *ngFor="let item of items; index as i" * ^^^^^ ^ * value key * ``` * * @param value name of the value in the declaration, "ngIf" in the example * above, along with its absolute span. */ parseAsBinding(value) { if (!this.peekKeywordAs()) { return null; } this.advance(); // consume the 'as' keyword const key = this.expectTemplateBindingKey(); this.consumeStatementTerminator(); const sourceSpan = new AbsoluteSourceSpan(value.span.start, this.currentAbsoluteOffset); return new VariableBinding(sourceSpan, key, value); } /** * Return the binding for a variable declared using `let`. For example, * ``` * *ngFor="let item of items; let i=index;" * ^^^^^^^^ ^^^^^^^^^^^ * ``` * In the first binding, `item` is bound to `NgForOfContext.$implicit`. * In the second binding, `i` is bound to `NgForOfContext.index`. */ parseLetBinding() { if (!this.peekKeywordLet()) { return null; } const spanStart = this.currentAbsoluteOffset; this.advance(); // consume the 'let' keyword const key = this.expectTemplateBindingKey(); let value = null; if (this.consumeOptionalOperator('=')) { value = this.expectTemplateBindingKey(); } this.consumeStatementTerminator(); const sourceSpan = new AbsoluteSourceSpan(spanStart, this.currentAbsoluteOffset); return new VariableBinding(sourceSpan, key, value); } /** * Consume the optional statement terminator: semicolon or comma. */ consumeStatementTerminator() { this.consumeOptionalCharacter(chars.$SEMICOLON) || this.consumeOptionalCharacter(chars.$COMMA); } /** * Records an error and skips over the token stream until reaching a recoverable point. See * `this.skip` for more details on token skipping. */ error(message, index = null) { this.errors.push(new ParserError(message, this.input, this.locationText(index), this.location)); this.skip(); } locationText(index = null) { if (index == null) index = this.index; return (index < this.tokens.length) ? `at column ${this.tokens[index].index + 1} in` : `at the end of the expression`; } /** * Records an error for an unexpected private identifier being discovered. * @param token Token representing a private identifier. * @param extraMessage Optional additional message being appended to the error. */ _reportErrorForPrivateIdentifier(token, extraMessage) { let errorMessage = `Private identifiers are not supported. Unexpected private identifier: ${token}`; if (extraMessage !== null) { errorMessage += `, ${extraMessage}`; } this.error(errorMessage); } /** * Error recovery should skip tokens until it encounters a recovery point. * * The following are treated as unconditional recovery points: * - end of input * - ';' (parseChain() is always the root production, and it expects a ';') * - '|' (since pipes may be chained and each pipe expression may be treated independently) * * The following are conditional recovery points: * - ')', '}', ']' if one of calling productions is expecting one of these symbols * - This allows skip() to recover from errors such as '(a.) + 1' allowing more of the AST to * be retained (it doesn't skip any tokens as the ')' is retained beca