@angular-devkit/build-optimizer
Version:
Angular Build Optimizer
115 lines (114 loc) • 4.99 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;
Object.defineProperty(o, k2, { enumerable: true, get: function() { return m[k]; } });
}) : (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.findTopLevelFunctions = exports.getPrefixFunctionsTransformer = void 0;
const ts = __importStar(require("typescript"));
const ast_utils_1 = require("../helpers/ast-utils");
function getPrefixFunctionsTransformer() {
return (context) => {
const transformer = (sf) => {
const topLevelFunctions = findTopLevelFunctions(sf);
const visitor = (node) => {
// Add pure function comment to top level functions.
if (topLevelFunctions.has(node)) {
const newNode = (0, ast_utils_1.addPureComment)(node);
// Replace node with modified one.
return ts.visitEachChild(newNode, visitor, context);
}
// Otherwise return node as is.
return ts.visitEachChild(node, visitor, context);
};
return ts.visitNode(sf, visitor);
};
return transformer;
};
}
exports.getPrefixFunctionsTransformer = getPrefixFunctionsTransformer;
function findTopLevelFunctions(parentNode) {
const topLevelFunctions = new Set();
function cb(node) {
// Stop recursing into this branch if it's a definition construct.
// These are function expression, function declaration, class, or arrow function (lambda).
// The body of these constructs will not execute when loading the module, so we don't
// need to mark function calls inside them as pure.
// Class static initializers in ES2015 are an exception we don't cover. They would need similar
// processing as enums to prevent property setting from causing the class to be retained.
if (ts.isFunctionLike(node) ||
ts.isClassLike(node) ||
ts.isArrowFunction(node) ||
ts.isMethodDeclaration(node)) {
return;
}
let noPureComment = !(0, ast_utils_1.hasPureComment)(node);
let innerNode = node;
while (innerNode && ts.isParenthesizedExpression(innerNode)) {
innerNode = innerNode.expression;
noPureComment = noPureComment && !(0, ast_utils_1.hasPureComment)(innerNode);
}
if (!innerNode) {
return;
}
if ((ts.isFunctionExpression(innerNode) || ts.isArrowFunction(innerNode)) &&
ts.isParenthesizedExpression(node)) {
// pure functions can be wrapped in parentizes
// we should not add pure comments to this sort of syntax.
// example var foo = (() => x)
return;
}
if (noPureComment) {
if (ts.isNewExpression(innerNode)) {
topLevelFunctions.add(node);
}
else if (ts.isCallExpression(innerNode)) {
let expression = innerNode.expression;
if (ts.isIdentifier(expression) && (0, ast_utils_1.getCleanHelperName)(expression.text)) {
return;
}
while (expression && ts.isParenthesizedExpression(expression)) {
expression = expression.expression;
}
if (expression) {
if (ts.isFunctionExpression(expression)) {
// Skip IIFE's with arguments
// This could be improved to check if there are any references to variables
if (innerNode.arguments.length === 0) {
topLevelFunctions.add(node);
}
}
else {
topLevelFunctions.add(node);
}
}
}
}
ts.forEachChild(innerNode, cb);
}
ts.forEachChild(parentNode, cb);
return topLevelFunctions;
}
exports.findTopLevelFunctions = findTopLevelFunctions;