285 lines
		
	
	
		
			8.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			285 lines
		
	
	
		
			8.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| "use strict";
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| 
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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.js");
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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 && !(grandparentPath.isAssignmentExpression() && parentPath.node === grandparentPath.node.left || grandparentPath.isLVal() || grandparentPath.isForXStatement() || grandparentPath.isUpdateExpression() || grandparentPath.isUnaryExpression({
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|           operator: "delete"
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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 (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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| 
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| //# sourceMappingURL=rest.js.map
 |