39 lines
1.2 KiB
Plaintext
39 lines
1.2 KiB
Plaintext
import {ContextualKeyword} from "../parser/tokenizer/keywords";
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/**
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* Determine whether this optional chain or nullish coalescing operation has any await statements in
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* it. If so, we'll need to transpile to an async operation.
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*
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* We compute this by walking the length of the operation and returning true if we see an await
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* keyword used as a real await (rather than an object key or property access). Nested optional
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* chain/nullish operations need to be tracked but don't silence await, but a nested async function
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* (or any other nested scope) will make the await not count.
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*/
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export default function isAsyncOperation(tokens) {
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let index = tokens.currentIndex();
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let depth = 0;
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const startToken = tokens.currentToken();
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do {
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const token = tokens.tokens[index];
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if (token.isOptionalChainStart) {
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depth++;
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}
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if (token.isOptionalChainEnd) {
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depth--;
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}
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depth += token.numNullishCoalesceStarts;
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depth -= token.numNullishCoalesceEnds;
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if (
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token.contextualKeyword === ContextualKeyword._await &&
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token.identifierRole == null &&
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token.scopeDepth === startToken.scopeDepth
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) {
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return true;
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}
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index += 1;
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} while (depth > 0 && index < tokens.tokens.length);
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return false;
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}
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