40e43f5a14
* Add test case demonstrating invalid behavior * Add conditional check for child properties so RHS is not duplicated * Add recursive check to find any nested non single-property case * Add case for array destructuring * Add test case for a nested rest element * More safely recurse through array destructuring * Traverse assignment and nested rest operations * Refactor to be more clear which case statement we are executing against * Update missed snapshots * Update packages/babel-plugin-proposal-object-rest-spread/src/index.js Co-authored-by: Huáng Jùnliàng <jlhwung@gmail.com> * Filter null array elements, add early return, remove optional chaining * Use stronger type assertions * Update fall through to be false; add early return to RestElement case * Move hasMoreThanOneBinding to its own file with distinct tests * Rename testing helper to more appropriately match business logic * Yarn Dedup & rename hasMoreThanOneBinding to shouldStoreRHSInTemporaryVariable Co-authored-by: Huáng Jùnliàng <jlhwung@gmail.com>
31 lines
1.2 KiB
JavaScript
31 lines
1.2 KiB
JavaScript
import { types as t } from "@babel/core";
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/**
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* This is a helper function to determine if we should create an intermediate variable
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* such that the RHS of an assignment is not duplicated.
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*
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* See https://github.com/babel/babel/pull/13711#issuecomment-914388382 for discussion
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* on further optimizations.
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*/
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export default function shouldStoreRHSInTemporaryVariable(node) {
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if (t.isArrayPattern(node)) {
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const nonNullElements = node.elements.filter(element => element !== null);
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if (nonNullElements.length > 1) return true;
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else return shouldStoreRHSInTemporaryVariable(nonNullElements[0]);
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} else if (t.isObjectPattern(node)) {
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if (node.properties.length > 1) return true;
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else if (node.properties.length === 0) return false;
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else return shouldStoreRHSInTemporaryVariable(node.properties[0]);
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} else if (t.isObjectProperty(node)) {
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return shouldStoreRHSInTemporaryVariable(node.value);
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} else if (t.isAssignmentPattern(node)) {
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return shouldStoreRHSInTemporaryVariable(node.left);
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} else if (t.isRestElement(node)) {
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if (t.isIdentifier(node.argument)) return true;
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return shouldStoreRHSInTemporaryVariable(node.argument);
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} else {
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// node is Identifier or MemberExpression
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return false;
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}
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}
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