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							306 lines
						
					
					
						
							8.6 KiB
						
					
					
				
			
		
		
	
	
							306 lines
						
					
					
						
							8.6 KiB
						
					
					
				"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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