@angular-devkit/build-optimizer/src/transforms/prefix-functions.js

"use strict";
/**
 * @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 = 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 = !ast_utils_1.hasPureComment(node);
        let innerNode = node;
        while (innerNode && ts.isParenthesizedExpression(innerNode)) {
            innerNode = innerNode.expression;
            noPureComment = noPureComment && !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) && 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;