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4 |
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5 | "use strict";
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6 |
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7 |
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8 |
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9 |
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10 |
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11 |
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12 | const addToSet = (a, b) => {
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13 | for (const item of b) {
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14 | if (!a.includes(item)) a.push(item);
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15 | }
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16 | return a;
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17 | };
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18 |
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19 | const isSubset = (biggerSet, subset) => {
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20 | if (biggerSet === true) return true;
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21 | if (subset === true) return false;
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22 | return subset.every(item => biggerSet.indexOf(item) >= 0);
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23 | };
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24 |
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25 | class FlagDependencyUsagePlugin {
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26 | apply(compiler) {
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27 | compiler.hooks.compilation.tap("FlagDependencyUsagePlugin", compilation => {
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28 | compilation.hooks.optimizeDependencies.tap(
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29 | "FlagDependencyUsagePlugin",
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30 | modules => {
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31 | const processModule = (module, usedExports) => {
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32 | module.used = true;
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33 | if (module.usedExports === true) return;
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34 | if (usedExports === true) {
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35 | module.usedExports = true;
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36 | } else if (Array.isArray(usedExports)) {
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37 | const old = module.usedExports ? module.usedExports.length : -1;
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38 | module.usedExports = addToSet(
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39 | module.usedExports || [],
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40 | usedExports
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41 | );
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42 | if (module.usedExports.length === old) {
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43 | return;
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44 | }
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45 | } else if (Array.isArray(module.usedExports)) {
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46 | return;
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47 | } else {
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48 | module.usedExports = false;
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49 | }
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50 |
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51 |
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52 |
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53 | if (module.factoryMeta.sideEffectFree) {
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54 | if (module.usedExports === false) return;
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55 | if (
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56 | Array.isArray(module.usedExports) &&
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57 | module.usedExports.length === 0
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58 | )
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59 | return;
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60 | }
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61 |
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62 | queue.push([module, module, module.usedExports]);
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63 | };
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64 |
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65 | const processDependenciesBlock = (module, depBlock, usedExports) => {
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66 | for (const dep of depBlock.dependencies) {
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67 | processDependency(module, dep);
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68 | }
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69 | for (const variable of depBlock.variables) {
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70 | for (const dep of variable.dependencies) {
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71 | processDependency(module, dep);
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72 | }
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73 | }
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74 | for (const block of depBlock.blocks) {
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75 | queue.push([module, block, usedExports]);
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76 | }
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77 | };
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78 |
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79 | const processDependency = (module, dep) => {
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80 | const reference = compilation.getDependencyReference(module, dep);
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81 | if (!reference) return;
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82 | const referenceModule = reference.module;
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83 | const importedNames = reference.importedNames;
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84 | const oldUsed = referenceModule.used;
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85 | const oldUsedExports = referenceModule.usedExports;
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86 | if (
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87 | !oldUsed ||
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88 | (importedNames &&
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89 | (!oldUsedExports || !isSubset(oldUsedExports, importedNames)))
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90 | ) {
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91 | processModule(referenceModule, importedNames);
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92 | }
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93 | };
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94 |
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95 | for (const module of modules) {
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96 | module.used = false;
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97 | }
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98 |
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99 |
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100 | const queue = [];
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101 | for (const preparedEntrypoint of compilation._preparedEntrypoints) {
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102 | if (preparedEntrypoint.module) {
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103 | processModule(preparedEntrypoint.module, true);
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104 | }
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105 | }
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106 |
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107 | while (queue.length) {
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108 | const queueItem = queue.pop();
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109 | processDependenciesBlock(queueItem[0], queueItem[1], queueItem[2]);
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110 | }
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111 | }
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112 | );
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113 | });
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114 | }
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115 | }
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116 | module.exports = FlagDependencyUsagePlugin;
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