File: /var/www/vhost/disk-apps/alq-cali.bikenow.co/node_modules/webpack/lib/ConstPlugin.js
/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const {
JAVASCRIPT_MODULE_TYPE_AUTO,
JAVASCRIPT_MODULE_TYPE_DYNAMIC,
JAVASCRIPT_MODULE_TYPE_ESM
} = require("./ModuleTypeConstants");
const CachedConstDependency = require("./dependencies/CachedConstDependency");
const ConstDependency = require("./dependencies/ConstDependency");
const { evaluateToString } = require("./javascript/JavascriptParserHelpers");
const { parseResource } = require("./util/identifier");
/** @typedef {import("estree").AssignmentProperty} AssignmentProperty */
/** @typedef {import("estree").Expression} Expression */
/** @typedef {import("estree").Identifier} Identifier */
/** @typedef {import("estree").Pattern} Pattern */
/** @typedef {import("estree").SourceLocation} SourceLocation */
/** @typedef {import("estree").Statement} Statement */
/** @typedef {import("estree").Super} Super */
/** @typedef {import("estree").VariableDeclaration} VariableDeclaration */
/** @typedef {import("./Compiler")} Compiler */
/** @typedef {import("./javascript/BasicEvaluatedExpression")} BasicEvaluatedExpression */
/** @typedef {import("./javascript/JavascriptParser")} JavascriptParser */
/** @typedef {import("./javascript/JavascriptParser").Range} Range */
/**
* @param {Set<string>} declarations set of declarations
* @param {Identifier | Pattern} pattern pattern to collect declarations from
*/
const collectDeclaration = (declarations, pattern) => {
const stack = [pattern];
while (stack.length > 0) {
const node = /** @type {Pattern} */ (stack.pop());
switch (node.type) {
case "Identifier":
declarations.add(node.name);
break;
case "ArrayPattern":
for (const element of node.elements) {
if (element) {
stack.push(element);
}
}
break;
case "AssignmentPattern":
stack.push(node.left);
break;
case "ObjectPattern":
for (const property of node.properties) {
stack.push(/** @type {AssignmentProperty} */ (property).value);
}
break;
case "RestElement":
stack.push(node.argument);
break;
}
}
};
/**
* @param {Statement} branch branch to get hoisted declarations from
* @param {boolean} includeFunctionDeclarations whether to include function declarations
* @returns {Array<string>} hoisted declarations
*/
const getHoistedDeclarations = (branch, includeFunctionDeclarations) => {
/** @type {Set<string>} */
const declarations = new Set();
/** @type {Array<Statement | null | undefined>} */
const stack = [branch];
while (stack.length > 0) {
const node = stack.pop();
// Some node could be `null` or `undefined`.
if (!node) continue;
switch (node.type) {
// Walk through control statements to look for hoisted declarations.
// Some branches are skipped since they do not allow declarations.
case "BlockStatement":
for (const stmt of node.body) {
stack.push(stmt);
}
break;
case "IfStatement":
stack.push(node.consequent);
stack.push(node.alternate);
break;
case "ForStatement":
stack.push(/** @type {VariableDeclaration} */ (node.init));
stack.push(node.body);
break;
case "ForInStatement":
case "ForOfStatement":
stack.push(/** @type {VariableDeclaration} */ (node.left));
stack.push(node.body);
break;
case "DoWhileStatement":
case "WhileStatement":
case "LabeledStatement":
stack.push(node.body);
break;
case "SwitchStatement":
for (const cs of node.cases) {
for (const consequent of cs.consequent) {
stack.push(consequent);
}
}
break;
case "TryStatement":
stack.push(node.block);
if (node.handler) {
stack.push(node.handler.body);
}
stack.push(node.finalizer);
break;
case "FunctionDeclaration":
if (includeFunctionDeclarations) {
collectDeclaration(declarations, /** @type {Identifier} */ (node.id));
}
break;
case "VariableDeclaration":
if (node.kind === "var") {
for (const decl of node.declarations) {
collectDeclaration(declarations, decl.id);
}
}
break;
}
}
return [...declarations];
};
const PLUGIN_NAME = "ConstPlugin";
class ConstPlugin {
/**
* Apply the plugin
* @param {Compiler} compiler the compiler instance
* @returns {void}
*/
apply(compiler) {
const cachedParseResource = parseResource.bindCache(compiler.root);
compiler.hooks.compilation.tap(
PLUGIN_NAME,
(compilation, { normalModuleFactory }) => {
compilation.dependencyTemplates.set(
ConstDependency,
new ConstDependency.Template()
);
compilation.dependencyTemplates.set(
CachedConstDependency,
new CachedConstDependency.Template()
);
/**
* @param {JavascriptParser} parser the parser
*/
const handler = (parser) => {
parser.hooks.terminate.tap(PLUGIN_NAME, (_statement) => true);
parser.hooks.statementIf.tap(PLUGIN_NAME, (statement) => {
if (parser.scope.isAsmJs) return;
const param = parser.evaluateExpression(statement.test);
const bool = param.asBool();
if (typeof bool === "boolean") {
if (!param.couldHaveSideEffects()) {
const dep = new ConstDependency(
`${bool}`,
/** @type {Range} */ (param.range)
);
dep.loc = /** @type {SourceLocation} */ (statement.loc);
parser.state.module.addPresentationalDependency(dep);
} else {
parser.walkExpression(statement.test);
}
const branchToRemove = bool
? statement.alternate
: statement.consequent;
if (branchToRemove) {
this.eliminateUnusedStatement(parser, branchToRemove, true);
}
return bool;
}
});
parser.hooks.unusedStatement.tap(PLUGIN_NAME, (statement) => {
if (
parser.scope.isAsmJs ||
// Check top level scope here again
parser.scope.topLevelScope === true
) {
return;
}
this.eliminateUnusedStatement(parser, statement, false);
return true;
});
parser.hooks.expressionConditionalOperator.tap(
PLUGIN_NAME,
(expression) => {
if (parser.scope.isAsmJs) return;
const param = parser.evaluateExpression(expression.test);
const bool = param.asBool();
if (typeof bool === "boolean") {
if (!param.couldHaveSideEffects()) {
const dep = new ConstDependency(
` ${bool}`,
/** @type {Range} */ (param.range)
);
dep.loc = /** @type {SourceLocation} */ (expression.loc);
parser.state.module.addPresentationalDependency(dep);
} else {
parser.walkExpression(expression.test);
}
// Expressions do not hoist.
// It is safe to remove the dead branch.
//
// Given the following code:
//
// false ? someExpression() : otherExpression();
//
// the generated code is:
//
// false ? 0 : otherExpression();
//
const branchToRemove = bool
? expression.alternate
: expression.consequent;
const dep = new ConstDependency(
"0",
/** @type {Range} */ (branchToRemove.range)
);
dep.loc = /** @type {SourceLocation} */ (branchToRemove.loc);
parser.state.module.addPresentationalDependency(dep);
return bool;
}
}
);
parser.hooks.expressionLogicalOperator.tap(
PLUGIN_NAME,
(expression) => {
if (parser.scope.isAsmJs) return;
if (
expression.operator === "&&" ||
expression.operator === "||"
) {
const param = parser.evaluateExpression(expression.left);
const bool = param.asBool();
if (typeof bool === "boolean") {
// Expressions do not hoist.
// It is safe to remove the dead branch.
//
// ------------------------------------------
//
// Given the following code:
//
// falsyExpression() && someExpression();
//
// the generated code is:
//
// falsyExpression() && false;
//
// ------------------------------------------
//
// Given the following code:
//
// truthyExpression() && someExpression();
//
// the generated code is:
//
// true && someExpression();
//
// ------------------------------------------
//
// Given the following code:
//
// truthyExpression() || someExpression();
//
// the generated code is:
//
// truthyExpression() || false;
//
// ------------------------------------------
//
// Given the following code:
//
// falsyExpression() || someExpression();
//
// the generated code is:
//
// false && someExpression();
//
const keepRight =
(expression.operator === "&&" && bool) ||
(expression.operator === "||" && !bool);
if (
!param.couldHaveSideEffects() &&
(param.isBoolean() || keepRight)
) {
// for case like
//
// return'development'===process.env.NODE_ENV&&'foo'
//
// we need a space before the bool to prevent result like
//
// returnfalse&&'foo'
//
const dep = new ConstDependency(
` ${bool}`,
/** @type {Range} */ (param.range)
);
dep.loc = /** @type {SourceLocation} */ (expression.loc);
parser.state.module.addPresentationalDependency(dep);
} else {
parser.walkExpression(expression.left);
}
if (!keepRight) {
const dep = new ConstDependency(
"0",
/** @type {Range} */ (expression.right.range)
);
dep.loc = /** @type {SourceLocation} */ (expression.loc);
parser.state.module.addPresentationalDependency(dep);
}
return keepRight;
}
} else if (expression.operator === "??") {
const param = parser.evaluateExpression(expression.left);
const keepRight = param.asNullish();
if (typeof keepRight === "boolean") {
// ------------------------------------------
//
// Given the following code:
//
// nonNullish ?? someExpression();
//
// the generated code is:
//
// nonNullish ?? 0;
//
// ------------------------------------------
//
// Given the following code:
//
// nullish ?? someExpression();
//
// the generated code is:
//
// null ?? someExpression();
//
if (!param.couldHaveSideEffects() && keepRight) {
// cspell:word returnnull
// for case like
//
// return('development'===process.env.NODE_ENV&&null)??'foo'
//
// we need a space before the bool to prevent result like
//
// returnnull??'foo'
//
const dep = new ConstDependency(
" null",
/** @type {Range} */ (param.range)
);
dep.loc = /** @type {SourceLocation} */ (expression.loc);
parser.state.module.addPresentationalDependency(dep);
} else {
const dep = new ConstDependency(
"0",
/** @type {Range} */ (expression.right.range)
);
dep.loc = /** @type {SourceLocation} */ (expression.loc);
parser.state.module.addPresentationalDependency(dep);
parser.walkExpression(expression.left);
}
return keepRight;
}
}
}
);
parser.hooks.optionalChaining.tap(PLUGIN_NAME, (expr) => {
/** @type {Expression[]} */
const optionalExpressionsStack = [];
/** @type {Expression | Super} */
let next = expr.expression;
while (
next.type === "MemberExpression" ||
next.type === "CallExpression"
) {
if (next.type === "MemberExpression") {
if (next.optional) {
// SuperNode can not be optional
optionalExpressionsStack.push(
/** @type {Expression} */ (next.object)
);
}
next = next.object;
} else {
if (next.optional) {
// SuperNode can not be optional
optionalExpressionsStack.push(
/** @type {Expression} */ (next.callee)
);
}
next = next.callee;
}
}
while (optionalExpressionsStack.length) {
const expression = optionalExpressionsStack.pop();
const evaluated = parser.evaluateExpression(
/** @type {Expression} */ (expression)
);
if (evaluated.asNullish()) {
// ------------------------------------------
//
// Given the following code:
//
// nullishMemberChain?.a.b();
//
// the generated code is:
//
// undefined;
//
// ------------------------------------------
//
const dep = new ConstDependency(
" undefined",
/** @type {Range} */ (expr.range)
);
dep.loc = /** @type {SourceLocation} */ (expr.loc);
parser.state.module.addPresentationalDependency(dep);
return true;
}
}
});
parser.hooks.evaluateIdentifier
.for("__resourceQuery")
.tap(PLUGIN_NAME, (expr) => {
if (parser.scope.isAsmJs) return;
if (!parser.state.module) return;
return evaluateToString(
cachedParseResource(parser.state.module.resource).query
)(expr);
});
parser.hooks.expression
.for("__resourceQuery")
.tap(PLUGIN_NAME, (expr) => {
if (parser.scope.isAsmJs) return;
if (!parser.state.module) return;
const dep = new CachedConstDependency(
JSON.stringify(
cachedParseResource(parser.state.module.resource).query
),
/** @type {Range} */ (expr.range),
"__resourceQuery"
);
dep.loc = /** @type {SourceLocation} */ (expr.loc);
parser.state.module.addPresentationalDependency(dep);
return true;
});
parser.hooks.evaluateIdentifier
.for("__resourceFragment")
.tap(PLUGIN_NAME, (expr) => {
if (parser.scope.isAsmJs) return;
if (!parser.state.module) return;
return evaluateToString(
cachedParseResource(parser.state.module.resource).fragment
)(expr);
});
parser.hooks.expression
.for("__resourceFragment")
.tap(PLUGIN_NAME, (expr) => {
if (parser.scope.isAsmJs) return;
if (!parser.state.module) return;
const dep = new CachedConstDependency(
JSON.stringify(
cachedParseResource(parser.state.module.resource).fragment
),
/** @type {Range} */ (expr.range),
"__resourceFragment"
);
dep.loc = /** @type {SourceLocation} */ (expr.loc);
parser.state.module.addPresentationalDependency(dep);
return true;
});
};
normalModuleFactory.hooks.parser
.for(JAVASCRIPT_MODULE_TYPE_AUTO)
.tap(PLUGIN_NAME, handler);
normalModuleFactory.hooks.parser
.for(JAVASCRIPT_MODULE_TYPE_DYNAMIC)
.tap(PLUGIN_NAME, handler);
normalModuleFactory.hooks.parser
.for(JAVASCRIPT_MODULE_TYPE_ESM)
.tap(PLUGIN_NAME, handler);
}
);
}
/**
* Eliminate an unused statement.
* @param {JavascriptParser} parser the parser
* @param {Statement} statement the statement to remove
* @param {boolean} alwaysInBlock whether to always generate curly brackets
* @returns {void}
*/
eliminateUnusedStatement(parser, statement, alwaysInBlock) {
// Before removing the unused branch, the hoisted declarations
// must be collected.
//
// Given the following code:
//
// if (true) f() else g()
// if (false) {
// function f() {}
// const g = function g() {}
// if (someTest) {
// let a = 1
// var x, {y, z} = obj
// }
// } else {
// …
// }
//
// the generated code is:
//
// if (true) f() else {}
// if (false) {
// var f, x, y, z; (in loose mode)
// var x, y, z; (in strict mode)
// } else {
// …
// }
//
// NOTE: When code runs in strict mode, `var` declarations
// are hoisted but `function` declarations don't.
//
const declarations = parser.scope.isStrict
? getHoistedDeclarations(statement, false)
: getHoistedDeclarations(statement, true);
const inBlock = alwaysInBlock || statement.type === "BlockStatement";
let replacement = inBlock ? "{" : "";
replacement +=
declarations.length > 0 ? ` var ${declarations.join(", ")}; ` : "";
replacement += inBlock ? "}" : "";
const dep = new ConstDependency(
`// removed by dead control flow\n${replacement}`,
/** @type {Range} */ (statement.range)
);
dep.loc = /** @type {SourceLocation} */ (statement.loc);
parser.state.module.addPresentationalDependency(dep);
}
}
module.exports = ConstPlugin;