jsep
Version:
a tiny JavaScript expression parser
1,127 lines (987 loc) • 28.2 kB
JavaScript
/**
* @implements {IHooks}
*/
class Hooks {
/**
* @callback HookCallback
* @this {*|Jsep} this
* @param {Jsep} env
* @returns: void
*/
/**
* Adds the given callback to the list of callbacks for the given hook.
*
* The callback will be invoked when the hook it is registered for is run.
*
* One callback function can be registered to multiple hooks and the same hook multiple times.
*
* @param {string|object} name The name of the hook, or an object of callbacks keyed by name
* @param {HookCallback|boolean} callback The callback function which is given environment variables.
* @param {?boolean} [first=false] Will add the hook to the top of the list (defaults to the bottom)
* @public
*/
add(name, callback, first) {
if (typeof arguments[0] != 'string') {
// Multiple hook callbacks, keyed by name
for (let name in arguments[0]) {
this.add(name, arguments[0][name], arguments[1]);
}
}
else {
(Array.isArray(name) ? name : [name]).forEach(function (name) {
this[name] = this[name] || [];
if (callback) {
this[name][first ? 'unshift' : 'push'](callback);
}
}, this);
}
}
/**
* Runs a hook invoking all registered callbacks with the given environment variables.
*
* Callbacks will be invoked synchronously and in the order in which they were registered.
*
* @param {string} name The name of the hook.
* @param {Object<string, any>} env The environment variables of the hook passed to all callbacks registered.
* @public
*/
run(name, env) {
this[name] = this[name] || [];
this[name].forEach(function (callback) {
callback.call(env && env.context ? env.context : env, env);
});
}
}
/**
* @implements {IPlugins}
*/
class Plugins {
constructor(jsep) {
this.jsep = jsep;
this.registered = {};
}
/**
* @callback PluginSetup
* @this {Jsep} jsep
* @returns: void
*/
/**
* Adds the given plugin(s) to the registry
*
* @param {object} plugins
* @param {string} plugins.name The name of the plugin
* @param {PluginSetup} plugins.init The init function
* @public
*/
register(...plugins) {
plugins.forEach((plugin) => {
if (typeof plugin !== 'object' || !plugin.name || !plugin.init) {
throw new Error('Invalid JSEP plugin format');
}
if (this.registered[plugin.name]) {
// already registered. Ignore.
return;
}
plugin.init(this.jsep);
this.registered[plugin.name] = plugin;
});
}
}
// JavaScript Expression Parser (JSEP) 1.4.0
class Jsep {
/**
* @returns {string}
*/
static get version() {
// To be filled in by the template
return '1.4.0';
}
/**
* @returns {string}
*/
static toString() {
return 'JavaScript Expression Parser (JSEP) v' + Jsep.version;
};
// ==================== CONFIG ================================
/**
* @method addUnaryOp
* @param {string} op_name The name of the unary op to add
* @returns {Jsep}
*/
static addUnaryOp(op_name) {
Jsep.max_unop_len = Math.max(op_name.length, Jsep.max_unop_len);
Jsep.unary_ops[op_name] = 1;
return Jsep;
}
/**
* @method jsep.addBinaryOp
* @param {string} op_name The name of the binary op to add
* @param {number} precedence The precedence of the binary op (can be a float). Higher number = higher precedence
* @param {boolean} [isRightAssociative=false] whether operator is right-associative
* @returns {Jsep}
*/
static addBinaryOp(op_name, precedence, isRightAssociative) {
Jsep.max_binop_len = Math.max(op_name.length, Jsep.max_binop_len);
Jsep.binary_ops[op_name] = precedence;
if (isRightAssociative) {
Jsep.right_associative.add(op_name);
}
else {
Jsep.right_associative.delete(op_name);
}
return Jsep;
}
/**
* @method addIdentifierChar
* @param {string} char The additional character to treat as a valid part of an identifier
* @returns {Jsep}
*/
static addIdentifierChar(char) {
Jsep.additional_identifier_chars.add(char);
return Jsep;
}
/**
* @method addLiteral
* @param {string} literal_name The name of the literal to add
* @param {*} literal_value The value of the literal
* @returns {Jsep}
*/
static addLiteral(literal_name, literal_value) {
Jsep.literals[literal_name] = literal_value;
return Jsep;
}
/**
* @method removeUnaryOp
* @param {string} op_name The name of the unary op to remove
* @returns {Jsep}
*/
static removeUnaryOp(op_name) {
delete Jsep.unary_ops[op_name];
if (op_name.length === Jsep.max_unop_len) {
Jsep.max_unop_len = Jsep.getMaxKeyLen(Jsep.unary_ops);
}
return Jsep;
}
/**
* @method removeAllUnaryOps
* @returns {Jsep}
*/
static removeAllUnaryOps() {
Jsep.unary_ops = {};
Jsep.max_unop_len = 0;
return Jsep;
}
/**
* @method removeIdentifierChar
* @param {string} char The additional character to stop treating as a valid part of an identifier
* @returns {Jsep}
*/
static removeIdentifierChar(char) {
Jsep.additional_identifier_chars.delete(char);
return Jsep;
}
/**
* @method removeBinaryOp
* @param {string} op_name The name of the binary op to remove
* @returns {Jsep}
*/
static removeBinaryOp(op_name) {
delete Jsep.binary_ops[op_name];
if (op_name.length === Jsep.max_binop_len) {
Jsep.max_binop_len = Jsep.getMaxKeyLen(Jsep.binary_ops);
}
Jsep.right_associative.delete(op_name);
return Jsep;
}
/**
* @method removeAllBinaryOps
* @returns {Jsep}
*/
static removeAllBinaryOps() {
Jsep.binary_ops = {};
Jsep.max_binop_len = 0;
return Jsep;
}
/**
* @method removeLiteral
* @param {string} literal_name The name of the literal to remove
* @returns {Jsep}
*/
static removeLiteral(literal_name) {
delete Jsep.literals[literal_name];
return Jsep;
}
/**
* @method removeAllLiterals
* @returns {Jsep}
*/
static removeAllLiterals() {
Jsep.literals = {};
return Jsep;
}
// ==================== END CONFIG ============================
/**
* @returns {string}
*/
get char() {
return this.expr.charAt(this.index);
}
/**
* @returns {number}
*/
get code() {
return this.expr.charCodeAt(this.index);
};
/**
* @param {string} expr a string with the passed in express
* @returns Jsep
*/
constructor(expr) {
// `index` stores the character number we are currently at
// All of the gobbles below will modify `index` as we move along
this.expr = expr;
this.index = 0;
}
/**
* static top-level parser
* @returns {jsep.Expression}
*/
static parse(expr) {
return (new Jsep(expr)).parse();
}
/**
* Get the longest key length of any object
* @param {object} obj
* @returns {number}
*/
static getMaxKeyLen(obj) {
return Math.max(0, ...Object.keys(obj).map(k => k.length));
}
/**
* `ch` is a character code in the next three functions
* @param {number} ch
* @returns {boolean}
*/
static isDecimalDigit(ch) {
return (ch >= 48 && ch <= 57); // 0...9
}
/**
* Returns the precedence of a binary operator or `0` if it isn't a binary operator. Can be float.
* @param {string} op_val
* @returns {number}
*/
static binaryPrecedence(op_val) {
return Jsep.binary_ops[op_val] || 0;
}
/**
* Looks for start of identifier
* @param {number} ch
* @returns {boolean}
*/
static isIdentifierStart(ch) {
return (ch >= 65 && ch <= 90) || // A...Z
(ch >= 97 && ch <= 122) || // a...z
(ch >= 128 && !Jsep.binary_ops[String.fromCharCode(ch)]) || // any non-ASCII that is not an operator
(Jsep.additional_identifier_chars.has(String.fromCharCode(ch))); // additional characters
}
/**
* @param {number} ch
* @returns {boolean}
*/
static isIdentifierPart(ch) {
return Jsep.isIdentifierStart(ch) || Jsep.isDecimalDigit(ch);
}
/**
* throw error at index of the expression
* @param {string} message
* @throws
*/
throwError(message) {
const error = new Error(message + ' at character ' + this.index);
error.index = this.index;
error.description = message;
throw error;
}
/**
* Run a given hook
* @param {string} name
* @param {jsep.Expression|false} [node]
* @returns {?jsep.Expression}
*/
runHook(name, node) {
if (Jsep.hooks[name]) {
const env = { context: this, node };
Jsep.hooks.run(name, env);
return env.node;
}
return node;
}
/**
* Runs a given hook until one returns a node
* @param {string} name
* @returns {?jsep.Expression}
*/
searchHook(name) {
if (Jsep.hooks[name]) {
const env = { context: this };
Jsep.hooks[name].find(function (callback) {
callback.call(env.context, env);
return env.node;
});
return env.node;
}
}
/**
* Push `index` up to the next non-space character
*/
gobbleSpaces() {
let ch = this.code;
// Whitespace
while (ch === Jsep.SPACE_CODE
|| ch === Jsep.TAB_CODE
|| ch === Jsep.LF_CODE
|| ch === Jsep.CR_CODE) {
ch = this.expr.charCodeAt(++this.index);
}
this.runHook('gobble-spaces');
}
/**
* Top-level method to parse all expressions and returns compound or single node
* @returns {jsep.Expression}
*/
parse() {
this.runHook('before-all');
const nodes = this.gobbleExpressions();
// If there's only one expression just try returning the expression
const node = nodes.length === 1
? nodes[0]
: {
type: Jsep.COMPOUND,
body: nodes
};
return this.runHook('after-all', node);
}
/**
* top-level parser (but can be reused within as well)
* @param {number} [untilICode]
* @returns {jsep.Expression[]}
*/
gobbleExpressions(untilICode) {
let nodes = [], ch_i, node;
while (this.index < this.expr.length) {
ch_i = this.code;
// Expressions can be separated by semicolons, commas, or just inferred without any
// separators
if (ch_i === Jsep.SEMCOL_CODE || ch_i === Jsep.COMMA_CODE) {
this.index++; // ignore separators
}
else {
// Try to gobble each expression individually
if (node = this.gobbleExpression()) {
nodes.push(node);
// If we weren't able to find a binary expression and are out of room, then
// the expression passed in probably has too much
}
else if (this.index < this.expr.length) {
if (ch_i === untilICode) {
break;
}
this.throwError('Unexpected "' + this.char + '"');
}
}
}
return nodes;
}
/**
* The main parsing function.
* @returns {?jsep.Expression}
*/
gobbleExpression() {
const node = this.searchHook('gobble-expression') || this.gobbleBinaryExpression();
this.gobbleSpaces();
return this.runHook('after-expression', node);
}
/**
* Search for the operation portion of the string (e.g. `+`, `===`)
* Start by taking the longest possible binary operations (3 characters: `===`, `!==`, `>>>`)
* and move down from 3 to 2 to 1 character until a matching binary operation is found
* then, return that binary operation
* @returns {string|boolean}
*/
gobbleBinaryOp() {
this.gobbleSpaces();
let to_check = this.expr.substr(this.index, Jsep.max_binop_len);
let tc_len = to_check.length;
while (tc_len > 0) {
// Don't accept a binary op when it is an identifier.
// Binary ops that start with a identifier-valid character must be followed
// by a non identifier-part valid character
if (Jsep.binary_ops.hasOwnProperty(to_check) && (
!Jsep.isIdentifierStart(this.code) ||
(this.index + to_check.length < this.expr.length && !Jsep.isIdentifierPart(this.expr.charCodeAt(this.index + to_check.length)))
)) {
this.index += tc_len;
return to_check;
}
to_check = to_check.substr(0, --tc_len);
}
return false;
}
/**
* This function is responsible for gobbling an individual expression,
* e.g. `1`, `1+2`, `a+(b*2)-Math.sqrt(2)`
* @returns {?jsep.BinaryExpression}
*/
gobbleBinaryExpression() {
let node, biop, prec, stack, biop_info, left, right, i, cur_biop;
// First, try to get the leftmost thing
// Then, check to see if there's a binary operator operating on that leftmost thing
// Don't gobbleBinaryOp without a left-hand-side
left = this.gobbleToken();
if (!left) {
return left;
}
biop = this.gobbleBinaryOp();
// If there wasn't a binary operator, just return the leftmost node
if (!biop) {
return left;
}
// Otherwise, we need to start a stack to properly place the binary operations in their
// precedence structure
biop_info = { value: biop, prec: Jsep.binaryPrecedence(biop), right_a: Jsep.right_associative.has(biop) };
right = this.gobbleToken();
if (!right) {
this.throwError("Expected expression after " + biop);
}
stack = [left, biop_info, right];
// Properly deal with precedence using [recursive descent](http://www.engr.mun.ca/~theo/Misc/exp_parsing.htm)
while ((biop = this.gobbleBinaryOp())) {
prec = Jsep.binaryPrecedence(biop);
if (prec === 0) {
this.index -= biop.length;
break;
}
biop_info = { value: biop, prec, right_a: Jsep.right_associative.has(biop) };
cur_biop = biop;
// Reduce: make a binary expression from the three topmost entries.
const comparePrev = prev => biop_info.right_a && prev.right_a
? prec > prev.prec
: prec <= prev.prec;
while ((stack.length > 2) && comparePrev(stack[stack.length - 2])) {
right = stack.pop();
biop = stack.pop().value;
left = stack.pop();
node = {
type: Jsep.BINARY_EXP,
operator: biop,
left,
right
};
stack.push(node);
}
node = this.gobbleToken();
if (!node) {
this.throwError("Expected expression after " + cur_biop);
}
stack.push(biop_info, node);
}
i = stack.length - 1;
node = stack[i];
while (i > 1) {
node = {
type: Jsep.BINARY_EXP,
operator: stack[i - 1].value,
left: stack[i - 2],
right: node
};
i -= 2;
}
return node;
}
/**
* An individual part of a binary expression:
* e.g. `foo.bar(baz)`, `1`, `"abc"`, `(a % 2)` (because it's in parenthesis)
* @returns {boolean|jsep.Expression}
*/
gobbleToken() {
let ch, to_check, tc_len, node;
this.gobbleSpaces();
node = this.searchHook('gobble-token');
if (node) {
return this.runHook('after-token', node);
}
ch = this.code;
if (Jsep.isDecimalDigit(ch) || ch === Jsep.PERIOD_CODE) {
// Char code 46 is a dot `.` which can start off a numeric literal
return this.gobbleNumericLiteral();
}
if (ch === Jsep.SQUOTE_CODE || ch === Jsep.DQUOTE_CODE) {
// Single or double quotes
node = this.gobbleStringLiteral();
}
else if (ch === Jsep.OBRACK_CODE) {
node = this.gobbleArray();
}
else {
to_check = this.expr.substr(this.index, Jsep.max_unop_len);
tc_len = to_check.length;
while (tc_len > 0) {
// Don't accept an unary op when it is an identifier.
// Unary ops that start with a identifier-valid character must be followed
// by a non identifier-part valid character
if (Jsep.unary_ops.hasOwnProperty(to_check) && (
!Jsep.isIdentifierStart(this.code) ||
(this.index + to_check.length < this.expr.length && !Jsep.isIdentifierPart(this.expr.charCodeAt(this.index + to_check.length)))
)) {
this.index += tc_len;
const argument = this.gobbleToken();
if (!argument) {
this.throwError('missing unaryOp argument');
}
return this.runHook('after-token', {
type: Jsep.UNARY_EXP,
operator: to_check,
argument,
prefix: true
});
}
to_check = to_check.substr(0, --tc_len);
}
if (Jsep.isIdentifierStart(ch)) {
node = this.gobbleIdentifier();
if (Jsep.literals.hasOwnProperty(node.name)) {
node = {
type: Jsep.LITERAL,
value: Jsep.literals[node.name],
raw: node.name,
};
}
else if (node.name === Jsep.this_str) {
node = { type: Jsep.THIS_EXP };
}
}
else if (ch === Jsep.OPAREN_CODE) { // open parenthesis
node = this.gobbleGroup();
}
}
if (!node) {
return this.runHook('after-token', false);
}
node = this.gobbleTokenProperty(node);
return this.runHook('after-token', node);
}
/**
* Gobble properties of of identifiers/strings/arrays/groups.
* e.g. `foo`, `bar.baz`, `foo['bar'].baz`
* It also gobbles function calls:
* e.g. `Math.acos(obj.angle)`
* @param {jsep.Expression} node
* @returns {jsep.Expression}
*/
gobbleTokenProperty(node) {
this.gobbleSpaces();
let ch = this.code;
while (ch === Jsep.PERIOD_CODE || ch === Jsep.OBRACK_CODE || ch === Jsep.OPAREN_CODE || ch === Jsep.QUMARK_CODE) {
let optional;
if (ch === Jsep.QUMARK_CODE) {
if (this.expr.charCodeAt(this.index + 1) !== Jsep.PERIOD_CODE) {
break;
}
optional = true;
this.index += 2;
this.gobbleSpaces();
ch = this.code;
}
this.index++;
if (ch === Jsep.OBRACK_CODE) {
node = {
type: Jsep.MEMBER_EXP,
computed: true,
object: node,
property: this.gobbleExpression()
};
if (!node.property) {
this.throwError('Unexpected "' + this.char + '"');
}
this.gobbleSpaces();
ch = this.code;
if (ch !== Jsep.CBRACK_CODE) {
this.throwError('Unclosed [');
}
this.index++;
}
else if (ch === Jsep.OPAREN_CODE) {
// A function call is being made; gobble all the arguments
node = {
type: Jsep.CALL_EXP,
'arguments': this.gobbleArguments(Jsep.CPAREN_CODE),
callee: node
};
}
else if (ch === Jsep.PERIOD_CODE || optional) {
if (optional) {
this.index--;
}
this.gobbleSpaces();
node = {
type: Jsep.MEMBER_EXP,
computed: false,
object: node,
property: this.gobbleIdentifier(),
};
}
if (optional) {
node.optional = true;
} // else leave undefined for compatibility with esprima
this.gobbleSpaces();
ch = this.code;
}
return node;
}
/**
* Parse simple numeric literals: `12`, `3.4`, `.5`. Do this by using a string to
* keep track of everything in the numeric literal and then calling `parseFloat` on that string
* @returns {jsep.Literal}
*/
gobbleNumericLiteral() {
let number = '', ch, chCode;
while (Jsep.isDecimalDigit(this.code)) {
number += this.expr.charAt(this.index++);
}
if (this.code === Jsep.PERIOD_CODE) { // can start with a decimal marker
number += this.expr.charAt(this.index++);
while (Jsep.isDecimalDigit(this.code)) {
number += this.expr.charAt(this.index++);
}
}
ch = this.char;
if (ch === 'e' || ch === 'E') { // exponent marker
number += this.expr.charAt(this.index++);
ch = this.char;
if (ch === '+' || ch === '-') { // exponent sign
number += this.expr.charAt(this.index++);
}
while (Jsep.isDecimalDigit(this.code)) { // exponent itself
number += this.expr.charAt(this.index++);
}
if (!Jsep.isDecimalDigit(this.expr.charCodeAt(this.index - 1)) ) {
this.throwError('Expected exponent (' + number + this.char + ')');
}
}
chCode = this.code;
// Check to make sure this isn't a variable name that start with a number (123abc)
if (Jsep.isIdentifierStart(chCode)) {
this.throwError('Variable names cannot start with a number (' +
number + this.char + ')');
}
else if (chCode === Jsep.PERIOD_CODE || (number.length === 1 && number.charCodeAt(0) === Jsep.PERIOD_CODE)) {
this.throwError('Unexpected period');
}
return {
type: Jsep.LITERAL,
value: parseFloat(number),
raw: number
};
}
/**
* Parses a string literal, staring with single or double quotes with basic support for escape codes
* e.g. `"hello world"`, `'this is\nJSEP'`
* @returns {jsep.Literal}
*/
gobbleStringLiteral() {
let str = '';
const startIndex = this.index;
const quote = this.expr.charAt(this.index++);
let closed = false;
while (this.index < this.expr.length) {
let ch = this.expr.charAt(this.index++);
if (ch === quote) {
closed = true;
break;
}
else if (ch === '\\') {
// Check for all of the common escape codes
ch = this.expr.charAt(this.index++);
switch (ch) {
case 'n': str += '\n'; break;
case 'r': str += '\r'; break;
case 't': str += '\t'; break;
case 'b': str += '\b'; break;
case 'f': str += '\f'; break;
case 'v': str += '\x0B'; break;
default : str += ch;
}
}
else {
str += ch;
}
}
if (!closed) {
this.throwError('Unclosed quote after "' + str + '"');
}
return {
type: Jsep.LITERAL,
value: str,
raw: this.expr.substring(startIndex, this.index),
};
}
/**
* Gobbles only identifiers
* e.g.: `foo`, `_value`, `$x1`
* Also, this function checks if that identifier is a literal:
* (e.g. `true`, `false`, `null`) or `this`
* @returns {jsep.Identifier}
*/
gobbleIdentifier() {
let ch = this.code, start = this.index;
if (Jsep.isIdentifierStart(ch)) {
this.index++;
}
else {
this.throwError('Unexpected ' + this.char);
}
while (this.index < this.expr.length) {
ch = this.code;
if (Jsep.isIdentifierPart(ch)) {
this.index++;
}
else {
break;
}
}
return {
type: Jsep.IDENTIFIER,
name: this.expr.slice(start, this.index),
};
}
/**
* Gobbles a list of arguments within the context of a function call
* or array literal. This function also assumes that the opening character
* `(` or `[` has already been gobbled, and gobbles expressions and commas
* until the terminator character `)` or `]` is encountered.
* e.g. `foo(bar, baz)`, `my_func()`, or `[bar, baz]`
* @param {number} termination
* @returns {jsep.Expression[]}
*/
gobbleArguments(termination) {
const args = [];
let closed = false;
let separator_count = 0;
while (this.index < this.expr.length) {
this.gobbleSpaces();
let ch_i = this.code;
if (ch_i === termination) { // done parsing
closed = true;
this.index++;
if (termination === Jsep.CPAREN_CODE && separator_count && separator_count >= args.length){
this.throwError('Unexpected token ' + String.fromCharCode(termination));
}
break;
}
else if (ch_i === Jsep.COMMA_CODE) { // between expressions
this.index++;
separator_count++;
if (separator_count !== args.length) { // missing argument
if (termination === Jsep.CPAREN_CODE) {
this.throwError('Unexpected token ,');
}
else if (termination === Jsep.CBRACK_CODE) {
for (let arg = args.length; arg < separator_count; arg++) {
args.push(null);
}
}
}
}
else if (args.length !== separator_count && separator_count !== 0) {
// NOTE: `&& separator_count !== 0` allows for either all commas, or all spaces as arguments
this.throwError('Expected comma');
}
else {
const node = this.gobbleExpression();
if (!node || node.type === Jsep.COMPOUND) {
this.throwError('Expected comma');
}
args.push(node);
}
}
if (!closed) {
this.throwError('Expected ' + String.fromCharCode(termination));
}
return args;
}
/**
* Responsible for parsing a group of things within parentheses `()`
* that have no identifier in front (so not a function call)
* This function assumes that it needs to gobble the opening parenthesis
* and then tries to gobble everything within that parenthesis, assuming
* that the next thing it should see is the close parenthesis. If not,
* then the expression probably doesn't have a `)`
* @returns {boolean|jsep.Expression}
*/
gobbleGroup() {
this.index++;
let nodes = this.gobbleExpressions(Jsep.CPAREN_CODE);
if (this.code === Jsep.CPAREN_CODE) {
this.index++;
if (nodes.length === 1) {
return nodes[0];
}
else if (!nodes.length) {
return false;
}
else {
return {
type: Jsep.SEQUENCE_EXP,
expressions: nodes,
};
}
}
else {
this.throwError('Unclosed (');
}
}
/**
* Responsible for parsing Array literals `[1, 2, 3]`
* This function assumes that it needs to gobble the opening bracket
* and then tries to gobble the expressions as arguments.
* @returns {jsep.ArrayExpression}
*/
gobbleArray() {
this.index++;
return {
type: Jsep.ARRAY_EXP,
elements: this.gobbleArguments(Jsep.CBRACK_CODE)
};
}
}
// Static fields:
const hooks = new Hooks();
Object.assign(Jsep, {
hooks,
plugins: new Plugins(Jsep),
// Node Types
// ----------
// This is the full set of types that any JSEP node can be.
// Store them here to save space when minified
COMPOUND: 'Compound',
SEQUENCE_EXP: 'SequenceExpression',
IDENTIFIER: 'Identifier',
MEMBER_EXP: 'MemberExpression',
LITERAL: 'Literal',
THIS_EXP: 'ThisExpression',
CALL_EXP: 'CallExpression',
UNARY_EXP: 'UnaryExpression',
BINARY_EXP: 'BinaryExpression',
ARRAY_EXP: 'ArrayExpression',
TAB_CODE: 9,
LF_CODE: 10,
CR_CODE: 13,
SPACE_CODE: 32,
PERIOD_CODE: 46, // '.'
COMMA_CODE: 44, // ','
SQUOTE_CODE: 39, // single quote
DQUOTE_CODE: 34, // double quotes
OPAREN_CODE: 40, // (
CPAREN_CODE: 41, // )
OBRACK_CODE: 91, // [
CBRACK_CODE: 93, // ]
QUMARK_CODE: 63, // ?
SEMCOL_CODE: 59, // ;
COLON_CODE: 58, // :
// Operations
// ----------
// Use a quickly-accessible map to store all of the unary operators
// Values are set to `1` (it really doesn't matter)
unary_ops: {
'-': 1,
'!': 1,
'~': 1,
'+': 1
},
// Also use a map for the binary operations but set their values to their
// binary precedence for quick reference (higher number = higher precedence)
// see [Order of operations](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence)
binary_ops: {
'||': 1, '??': 1,
'&&': 2, '|': 3, '^': 4, '&': 5,
'==': 6, '!=': 6, '===': 6, '!==': 6,
'<': 7, '>': 7, '<=': 7, '>=': 7,
'<<': 8, '>>': 8, '>>>': 8,
'+': 9, '-': 9,
'*': 10, '/': 10, '%': 10,
'**': 11,
},
// sets specific binary_ops as right-associative
right_associative: new Set(['**']),
// Additional valid identifier chars, apart from a-z, A-Z and 0-9 (except on the starting char)
additional_identifier_chars: new Set(['$', '_']),
// Literals
// ----------
// Store the values to return for the various literals we may encounter
literals: {
'true': true,
'false': false,
'null': null
},
// Except for `this`, which is special. This could be changed to something like `'self'` as well
this_str: 'this',
});
Jsep.max_unop_len = Jsep.getMaxKeyLen(Jsep.unary_ops);
Jsep.max_binop_len = Jsep.getMaxKeyLen(Jsep.binary_ops);
// Backward Compatibility:
const jsep = expr => (new Jsep(expr)).parse();
const stdClassProps = Object.getOwnPropertyNames(class Test{});
Object.getOwnPropertyNames(Jsep)
.filter(prop => !stdClassProps.includes(prop) && jsep[prop] === undefined)
.forEach((m) => {
jsep[m] = Jsep[m];
});
jsep.Jsep = Jsep; // allows for const { Jsep } = require('jsep');
const CONDITIONAL_EXP = 'ConditionalExpression';
var ternary = {
name: 'ternary',
init(jsep) {
// Ternary expression: test ? consequent : alternate
jsep.hooks.add('after-expression', function gobbleTernary(env) {
if (env.node && this.code === jsep.QUMARK_CODE) {
this.index++;
const test = env.node;
const consequent = this.gobbleExpression();
if (!consequent) {
this.throwError('Expected expression');
}
this.gobbleSpaces();
if (this.code === jsep.COLON_CODE) {
this.index++;
const alternate = this.gobbleExpression();
if (!alternate) {
this.throwError('Expected expression');
}
env.node = {
type: CONDITIONAL_EXP,
test,
consequent,
alternate,
};
// check for operators of higher priority than ternary (i.e. assignment)
// jsep sets || at 1, and assignment at 0.9, and conditional should be between them
if (test.operator && jsep.binary_ops[test.operator] <= 0.9) {
let newTest = test;
while (newTest.right.operator && jsep.binary_ops[newTest.right.operator] <= 0.9) {
newTest = newTest.right;
}
env.node.test = newTest.right;
newTest.right = env.node;
env.node = test;
}
}
else {
this.throwError('Expected :');
}
}
});
},
};
// Add default plugins:
jsep.plugins.register(ternary);
export { Jsep, jsep as default };