354 lines
11 KiB
JavaScript
354 lines
11 KiB
JavaScript
"use strict"; // Assuming all the static methods from below array are side effect free evaluation
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// except Math.random
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function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _nonIterableRest(); }
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function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance"); }
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function _iterableToArrayLimit(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }
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function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }
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const VALID_CALLEES = ["String", "Number", "Math"];
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const INVALID_METHODS = ["random"];
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const newIssueUrl = "https://github.com/babel/minify/issues/new";
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module.exports = function ({
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types: t
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}) {
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class BuiltInReplacer {
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constructor() {
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// map<expr_name, path[]>;
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this.pathsToUpdate = new Map();
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}
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getCollectVisitor() {
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const context = this;
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const collectVisitor = {
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AssignmentExpression(path) {
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const left = path.node.left; // Should bail and not run the plugin
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// when builtin is polyfilled
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if (t.isMemberExpression(left) && isBuiltInComputed(left)) {
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let parent = path;
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do {
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parent.stop();
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} while (parent = parent.parentPath);
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}
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},
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MemberExpression(path) {
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if (path.parentPath.isCallExpression()) {
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return;
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}
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const node = path.node;
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if (!isComputed(node) && isBuiltin(node) && !getFunctionParent(path).isProgram()) {
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const expName = memberToString(node);
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addToMap(context.pathsToUpdate, expName, path);
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}
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},
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CallExpression: {
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exit(path) {
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const callee = path.get("callee");
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if (!callee.isMemberExpression()) {
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return;
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}
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const node = callee.node; // computed property should not be optimized
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// Math[max]() -> Math.max()
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if (!isComputed(node) && isBuiltin(node) && !getFunctionParent(callee).isProgram()) {
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const expName = memberToString(node);
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addToMap(context.pathsToUpdate, expName, callee);
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}
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}
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}
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};
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return collectVisitor;
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}
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replace() {
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var _iteratorNormalCompletion = true;
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var _didIteratorError = false;
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var _iteratorError = undefined;
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try {
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for (var _iterator = this.pathsToUpdate[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
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const _step$value = _slicedToArray(_step.value, 2),
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expName = _step$value[0],
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paths = _step$value[1];
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// transform only if there is more than 1 occurence
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if (paths.length <= 1) {
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continue;
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}
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const segmentsMap = getSegmentedSubPaths(paths);
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var _iteratorNormalCompletion2 = true;
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var _didIteratorError2 = false;
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var _iteratorError2 = undefined;
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try {
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for (var _iterator2 = segmentsMap[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
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const _step2$value = _slicedToArray(_step2.value, 2),
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parent = _step2$value[0],
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subpaths = _step2$value[1];
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if (subpaths.length <= 1) {
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continue;
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}
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const uniqueIdentifier = parent.scope.generateUidIdentifier(expName);
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const newNode = t.variableDeclaration("var", [t.variableDeclarator(uniqueIdentifier, subpaths[0].node)]);
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var _iteratorNormalCompletion3 = true;
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var _didIteratorError3 = false;
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var _iteratorError3 = undefined;
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try {
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for (var _iterator3 = subpaths[Symbol.iterator](), _step3; !(_iteratorNormalCompletion3 = (_step3 = _iterator3.next()).done); _iteratorNormalCompletion3 = true) {
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const path = _step3.value;
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path.replaceWith(t.clone(uniqueIdentifier));
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} // hoist the created var to the top of the function scope
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} catch (err) {
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_didIteratorError3 = true;
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_iteratorError3 = err;
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} finally {
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try {
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if (!_iteratorNormalCompletion3 && _iterator3.return != null) {
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_iterator3.return();
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}
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} finally {
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if (_didIteratorError3) {
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throw _iteratorError3;
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}
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}
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}
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const target = parent.get("body");
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/**
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* Here, we validate a case where there is a local binding of
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* one of Math, String or Number. Here we have to get the
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* global Math instead of using the local one - so we do the
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* following transformation
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*
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* var _Mathmax = Math.max;
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*
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* to
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*
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* var _Mathmax = (0, eval)("this").Math.max;
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*/
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for (var _i2 = 0; _i2 < VALID_CALLEES.length; _i2++) {
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const builtin = VALID_CALLEES[_i2];
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if (target.scope.getBinding(builtin)) {
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const prev = newNode.declarations[0].init;
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if (!t.isMemberExpression(prev)) {
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throw new Error(`minify-builtins expected a MemberExpression. ` + `Found ${prev.type}. ` + `Please report this at ${newIssueUrl}`);
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}
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if (!t.isMemberExpression(prev.object)) {
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newNode.declarations[0].init = t.memberExpression(t.memberExpression(getGlobalThis(), prev.object), prev.property);
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}
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}
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}
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target.unshiftContainer("body", newNode);
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}
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} catch (err) {
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_didIteratorError2 = true;
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_iteratorError2 = err;
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} finally {
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try {
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if (!_iteratorNormalCompletion2 && _iterator2.return != null) {
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_iterator2.return();
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}
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} finally {
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if (_didIteratorError2) {
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throw _iteratorError2;
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}
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}
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}
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}
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} catch (err) {
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_didIteratorError = true;
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_iteratorError = err;
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} finally {
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try {
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if (!_iteratorNormalCompletion && _iterator.return != null) {
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_iterator.return();
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}
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} finally {
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if (_didIteratorError) {
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throw _iteratorError;
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}
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}
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}
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}
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}
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const builtInReplacer = new BuiltInReplacer();
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return {
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name: "minify-builtins",
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visitor: Object.assign({}, builtInReplacer.getCollectVisitor(), {
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Program: {
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exit() {
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builtInReplacer.replace();
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}
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}
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})
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};
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function memberToString(memberExprNode) {
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const object = memberExprNode.object,
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property = memberExprNode.property;
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let result = "";
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if (t.isIdentifier(object)) result += object.name;
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if (t.isMemberExpression(object)) result += memberToString(object);
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if (t.isIdentifier(property)) result += property.name;
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return result;
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}
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function isBuiltInComputed(memberExprNode) {
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const object = memberExprNode.object,
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computed = memberExprNode.computed;
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return computed && t.isIdentifier(object) && VALID_CALLEES.indexOf(object.name) >= 0;
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}
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function isBuiltin(memberExprNode) {
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const object = memberExprNode.object,
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property = memberExprNode.property;
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if (t.isIdentifier(object) && t.isIdentifier(property) && VALID_CALLEES.indexOf(object.name) >= 0 && INVALID_METHODS.indexOf(property.name) < 0) {
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return true;
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}
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return false;
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} // Creates a segmented map that contains the earliest common Ancestor
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// as the key and array of subpaths that are descendats of the LCA as value
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function getSegmentedSubPaths(paths) {
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let segments = new Map(); // Get earliest Path in tree where paths intersect
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paths[0].getDeepestCommonAncestorFrom(paths, (lastCommon, index, ancestries) => {
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// found the LCA
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if (!lastCommon.isProgram()) {
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let fnParent;
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if (lastCommon.isFunction() && t.isBlockStatement(lastCommon.node.body)) {
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segments.set(lastCommon, paths);
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return;
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} else if (!(fnParent = getFunctionParent(lastCommon)).isProgram() && t.isBlockStatement(fnParent.node.body)) {
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segments.set(fnParent, paths);
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return;
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}
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} // Deopt and construct segments otherwise
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var _iteratorNormalCompletion4 = true;
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var _didIteratorError4 = false;
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var _iteratorError4 = undefined;
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try {
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for (var _iterator4 = ancestries[Symbol.iterator](), _step4; !(_iteratorNormalCompletion4 = (_step4 = _iterator4.next()).done); _iteratorNormalCompletion4 = true) {
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const ancestor = _step4.value;
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const fnPath = getChildFuncion(ancestor);
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if (fnPath === void 0) {
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continue;
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}
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const validDescendants = paths.filter(p => {
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return p.isDescendant(fnPath);
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});
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segments.set(fnPath, validDescendants);
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}
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} catch (err) {
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_didIteratorError4 = true;
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_iteratorError4 = err;
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} finally {
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try {
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if (!_iteratorNormalCompletion4 && _iterator4.return != null) {
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_iterator4.return();
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}
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} finally {
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if (_didIteratorError4) {
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throw _iteratorError4;
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}
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}
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}
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});
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return segments;
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}
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function getChildFuncion(ancestors = []) {
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var _iteratorNormalCompletion5 = true;
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var _didIteratorError5 = false;
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var _iteratorError5 = undefined;
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try {
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for (var _iterator5 = ancestors[Symbol.iterator](), _step5; !(_iteratorNormalCompletion5 = (_step5 = _iterator5.next()).done); _iteratorNormalCompletion5 = true) {
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const path = _step5.value;
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if (path.isFunction() && t.isBlockStatement(path.node.body)) {
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return path;
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}
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}
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} catch (err) {
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_didIteratorError5 = true;
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_iteratorError5 = err;
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} finally {
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try {
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if (!_iteratorNormalCompletion5 && _iterator5.return != null) {
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_iterator5.return();
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}
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} finally {
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if (_didIteratorError5) {
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throw _iteratorError5;
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}
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}
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}
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}
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/**
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* returns
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*
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* (0, eval)("this")
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*/
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function getGlobalThis() {
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return t.callExpression(t.sequenceExpression([t.valueToNode(0), t.identifier("eval")]), [t.valueToNode("this")]);
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}
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};
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function addToMap(map, key, value) {
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if (!map.has(key)) {
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map.set(key, []);
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}
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map.get(key).push(value);
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}
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function isComputed(node) {
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return node.computed;
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}
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/**
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* Babel-7 returns null if there is no function parent
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* and uses getProgramParent to get Program
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*/
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function getFunctionParent(path) {
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return (path.scope.getFunctionParent() || path.scope.getProgramParent()).path;
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} |