@ngtools/webpack
Version:
Webpack plugin that AoT compiles your Angular components and modules.
157 lines (156 loc) • 6.42 kB
JavaScript
;
/**
* @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
*/
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
var desc = Object.getOwnPropertyDescriptor(m, k);
if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
desc = { enumerable: true, get: function() { return m[k]; } };
}
Object.defineProperty(o, k2, desc);
}) : (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
__setModuleDefault(result, mod);
return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.elideImports = void 0;
const ts = __importStar(require("typescript"));
// Remove imports for which all identifiers have been removed.
// Needs type checker, and works even if it's not the first transformer.
// Works by removing imports for symbols whose identifiers have all been removed.
// Doesn't use the `symbol.declarations` because that previous transforms might have removed nodes
// but the type checker doesn't know.
// See https://github.com/Microsoft/TypeScript/issues/17552 for more information.
function elideImports(sourceFile, removedNodes, getTypeChecker, compilerOptions) {
const importNodeRemovals = new Set();
if (removedNodes.length === 0) {
return importNodeRemovals;
}
const typeChecker = getTypeChecker();
// Collect all imports and used identifiers
const usedSymbols = new Set();
const imports = [];
ts.forEachChild(sourceFile, function visit(node) {
// Skip removed nodes.
if (removedNodes.includes(node)) {
return;
}
// Consider types for 'implements' as unused.
// A HeritageClause token can also be an 'AbstractKeyword'
// which in that case we should not elide the import.
if (ts.isHeritageClause(node) && node.token === ts.SyntaxKind.ImplementsKeyword) {
return;
}
// Record import and skip
if (ts.isImportDeclaration(node)) {
if (!node.importClause?.isTypeOnly) {
imports.push(node);
}
return;
}
// Type reference imports do not need to be emitted when emitDecoratorMetadata is disabled.
if (ts.isTypeReferenceNode(node) && !compilerOptions.emitDecoratorMetadata) {
return;
}
let symbol;
switch (node.kind) {
case ts.SyntaxKind.Identifier:
const parent = node.parent;
if (parent && ts.isShorthandPropertyAssignment(parent)) {
const shorthandSymbol = typeChecker.getShorthandAssignmentValueSymbol(parent);
if (shorthandSymbol) {
symbol = shorthandSymbol;
}
}
else {
symbol = typeChecker.getSymbolAtLocation(node);
}
break;
case ts.SyntaxKind.ExportSpecifier:
symbol = typeChecker.getExportSpecifierLocalTargetSymbol(node);
break;
case ts.SyntaxKind.ShorthandPropertyAssignment:
symbol = typeChecker.getShorthandAssignmentValueSymbol(node);
break;
}
if (symbol) {
usedSymbols.add(symbol);
}
ts.forEachChild(node, visit);
});
if (imports.length === 0) {
return importNodeRemovals;
}
const isUnused = (node) => {
// Do not remove JSX factory imports
if (node.text === compilerOptions.jsxFactory) {
return false;
}
const symbol = typeChecker.getSymbolAtLocation(node);
return symbol && !usedSymbols.has(symbol);
};
for (const node of imports) {
if (!node.importClause) {
// "import 'abc';"
continue;
}
const namedBindings = node.importClause.namedBindings;
if (namedBindings && ts.isNamespaceImport(namedBindings)) {
// "import * as XYZ from 'abc';"
if (isUnused(namedBindings.name)) {
importNodeRemovals.add(node);
}
}
else {
const specifierNodeRemovals = [];
let clausesCount = 0;
// "import { XYZ, ... } from 'abc';"
if (namedBindings && ts.isNamedImports(namedBindings)) {
let removedClausesCount = 0;
clausesCount += namedBindings.elements.length;
for (const specifier of namedBindings.elements) {
if (specifier.isTypeOnly || isUnused(specifier.name)) {
removedClausesCount++;
// in case we don't have any more namedImports we should remove the parent ie the {}
const nodeToRemove = clausesCount === removedClausesCount ? specifier.parent : specifier;
specifierNodeRemovals.push(nodeToRemove);
}
}
}
// "import XYZ from 'abc';"
if (node.importClause.name) {
clausesCount++;
if (node.importClause.isTypeOnly || isUnused(node.importClause.name)) {
specifierNodeRemovals.push(node.importClause.name);
}
}
if (specifierNodeRemovals.length === clausesCount) {
importNodeRemovals.add(node);
}
else {
for (const specifierNodeRemoval of specifierNodeRemovals) {
importNodeRemovals.add(specifierNodeRemoval);
}
}
}
}
return importNodeRemovals;
}
exports.elideImports = elideImports;