"use strict";
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Object.defineProperty(exports, "__esModule", {
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value: true
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});
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exports.default = convertFunctionRest;
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var _core = require("@babel/core");
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var _shadowUtils = require("./shadow-utils");
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const buildRest = _core.template.statement(`
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for (var LEN = ARGUMENTS.length,
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ARRAY = new Array(ARRAY_LEN),
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KEY = START;
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KEY < LEN;
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KEY++) {
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ARRAY[ARRAY_KEY] = ARGUMENTS[KEY];
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}
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`);
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const restIndex = _core.template.expression(`
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(INDEX < OFFSET || ARGUMENTS.length <= INDEX) ? undefined : ARGUMENTS[INDEX]
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`);
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const restIndexImpure = _core.template.expression(`
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REF = INDEX, (REF < OFFSET || ARGUMENTS.length <= REF) ? undefined : ARGUMENTS[REF]
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`);
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const restLength = _core.template.expression(`
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ARGUMENTS.length <= OFFSET ? 0 : ARGUMENTS.length - OFFSET
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`);
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function referencesRest(path, state) {
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if (path.node.name === state.name) {
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return path.scope.bindingIdentifierEquals(state.name, state.outerBinding);
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}
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return false;
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}
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const memberExpressionOptimisationVisitor = {
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Scope(path, state) {
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if (!path.scope.bindingIdentifierEquals(state.name, state.outerBinding)) {
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path.skip();
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}
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},
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Flow(path) {
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if (path.isTypeCastExpression()) return;
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path.skip();
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},
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Function(path, state) {
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const oldNoOptimise = state.noOptimise;
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state.noOptimise = true;
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path.traverse(memberExpressionOptimisationVisitor, state);
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state.noOptimise = oldNoOptimise;
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path.skip();
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},
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ReferencedIdentifier(path, state) {
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const {
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node
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} = path;
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if (node.name === "arguments") {
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state.deopted = true;
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}
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if (!referencesRest(path, state)) return;
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if (state.noOptimise) {
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state.deopted = true;
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} else {
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const {
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parentPath
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} = path;
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if (parentPath.listKey === "params" && parentPath.key < state.offset) {
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return;
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}
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if (parentPath.isMemberExpression({
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object: node
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})) {
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const grandparentPath = parentPath.parentPath;
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const argsOptEligible = !state.deopted && !(
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grandparentPath.isAssignmentExpression() && parentPath.node === grandparentPath.node.left ||
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grandparentPath.isLVal() ||
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grandparentPath.isForXStatement() ||
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grandparentPath.isUpdateExpression() ||
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grandparentPath.isUnaryExpression({
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operator: "delete"
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}) ||
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(grandparentPath.isCallExpression() || grandparentPath.isNewExpression()) && parentPath.node === grandparentPath.node.callee);
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if (argsOptEligible) {
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if (parentPath.node.computed) {
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if (parentPath.get("property").isBaseType("number")) {
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state.candidates.push({
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cause: "indexGetter",
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path
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});
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return;
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}
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} else if (
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parentPath.node.property.name === "length") {
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state.candidates.push({
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cause: "lengthGetter",
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path
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});
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return;
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}
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}
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}
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if (state.offset === 0 && parentPath.isSpreadElement()) {
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const call = parentPath.parentPath;
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if (call.isCallExpression() && call.node.arguments.length === 1) {
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state.candidates.push({
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cause: "argSpread",
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path
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});
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return;
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}
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}
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state.references.push(path);
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}
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},
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BindingIdentifier(path, state) {
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if (referencesRest(path, state)) {
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state.deopted = true;
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}
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}
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};
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function getParamsCount(node) {
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let count = node.params.length;
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if (count > 0 && _core.types.isIdentifier(node.params[0], {
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name: "this"
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})) {
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count -= 1;
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}
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return count;
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}
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function hasRest(node) {
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const length = node.params.length;
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return length > 0 && _core.types.isRestElement(node.params[length - 1]);
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}
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function optimiseIndexGetter(path, argsId, offset) {
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const offsetLiteral = _core.types.numericLiteral(offset);
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let index;
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const parent = path.parent;
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if (_core.types.isNumericLiteral(parent.property)) {
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index = _core.types.numericLiteral(parent.property.value + offset);
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} else if (offset === 0) {
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index = parent.property;
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} else {
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index = _core.types.binaryExpression("+", parent.property, _core.types.cloneNode(offsetLiteral));
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}
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const {
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scope,
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parentPath
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} = path;
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if (!scope.isPure(index)) {
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const temp = scope.generateUidIdentifierBasedOnNode(index);
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scope.push({
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id: temp,
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kind: "var"
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});
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parentPath.replaceWith(restIndexImpure({
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ARGUMENTS: argsId,
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OFFSET: offsetLiteral,
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INDEX: index,
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REF: _core.types.cloneNode(temp)
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}));
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} else {
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parentPath.replaceWith(restIndex({
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ARGUMENTS: argsId,
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OFFSET: offsetLiteral,
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INDEX: index
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}));
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const replacedParentPath = parentPath;
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const offsetTestPath = replacedParentPath.get("test");
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const valRes = offsetTestPath.get("left").evaluate();
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if (valRes.confident) {
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if (valRes.value === true) {
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replacedParentPath.replaceWith(scope.buildUndefinedNode());
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} else {
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offsetTestPath.replaceWith(offsetTestPath.get("right"));
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}
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}
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}
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}
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function optimiseLengthGetter(path, argsId, offset) {
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if (offset) {
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path.parentPath.replaceWith(restLength({
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ARGUMENTS: argsId,
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OFFSET: _core.types.numericLiteral(offset)
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}));
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} else {
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path.replaceWith(argsId);
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}
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}
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function convertFunctionRest(path) {
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const {
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node,
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scope
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} = path;
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if (!hasRest(node)) return false;
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const restPath = path.get(`params.${node.params.length - 1}.argument`);
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if (!restPath.isIdentifier()) {
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const shadowedParams = new Set();
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(0, _shadowUtils.collectShadowedParamsNames)(restPath, path.scope, shadowedParams);
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let needsIIFE = shadowedParams.size > 0;
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if (!needsIIFE) {
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const state = {
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needsOuterBinding: false,
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scope
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};
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restPath.traverse(_shadowUtils.iifeVisitor, state);
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needsIIFE = state.needsOuterBinding;
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}
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if (needsIIFE) {
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path.ensureBlock();
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path.set("body", _core.types.blockStatement([(0, _shadowUtils.buildScopeIIFE)(shadowedParams, path.node.body)]));
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}
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}
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let rest = restPath.node;
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node.params.pop();
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if (_core.types.isPattern(rest)) {
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const pattern = rest;
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rest = scope.generateUidIdentifier("ref");
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const declar = _core.types.variableDeclaration("let", [_core.types.variableDeclarator(pattern, rest)]);
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path.ensureBlock();
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node.body.body.unshift(declar);
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} else if (rest.name === "arguments") {
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scope.rename(rest.name);
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}
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const argsId = _core.types.identifier("arguments");
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const paramsCount = getParamsCount(node);
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const state = {
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references: [],
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offset: paramsCount,
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argumentsNode: argsId,
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outerBinding: scope.getBindingIdentifier(rest.name),
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candidates: [],
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name: rest.name,
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deopted: false
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};
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path.traverse(memberExpressionOptimisationVisitor, state);
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if (!state.deopted && !state.references.length) {
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for (const {
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path,
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cause
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} of state.candidates) {
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const clonedArgsId = _core.types.cloneNode(argsId);
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switch (cause) {
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case "indexGetter":
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optimiseIndexGetter(path, clonedArgsId, state.offset);
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break;
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case "lengthGetter":
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optimiseLengthGetter(path, clonedArgsId, state.offset);
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break;
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default:
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path.replaceWith(clonedArgsId);
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}
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}
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return true;
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}
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state.references.push(...state.candidates.map(({
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path
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}) => path));
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const start = _core.types.numericLiteral(paramsCount);
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const key = scope.generateUidIdentifier("key");
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const len = scope.generateUidIdentifier("len");
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let arrKey, arrLen;
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if (paramsCount) {
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arrKey = _core.types.binaryExpression("-", _core.types.cloneNode(key), _core.types.cloneNode(start));
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arrLen = _core.types.conditionalExpression(_core.types.binaryExpression(">", _core.types.cloneNode(len), _core.types.cloneNode(start)), _core.types.binaryExpression("-", _core.types.cloneNode(len), _core.types.cloneNode(start)), _core.types.numericLiteral(0));
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} else {
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arrKey = _core.types.identifier(key.name);
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arrLen = _core.types.identifier(len.name);
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}
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const loop = buildRest({
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ARGUMENTS: argsId,
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ARRAY_KEY: arrKey,
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ARRAY_LEN: arrLen,
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START: start,
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ARRAY: rest,
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KEY: key,
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LEN: len
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});
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if (state.deopted) {
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node.body.body.unshift(loop);
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} else {
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let target = path.getEarliestCommonAncestorFrom(state.references).getStatementParent();
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target.findParent(path => {
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if (path.isLoop()) {
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target = path;
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} else {
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return path.isFunction();
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}
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});
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target.insertBefore(loop);
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}
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return true;
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}
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//# sourceMappingURL=rest.js.map
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