37 lines
1.7 KiB
Plaintext
37 lines
1.7 KiB
Plaintext
import type NameManager from "../NameManager";
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import type TokenProcessor from "../TokenProcessor";
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import Transformer from "./Transformer";
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/**
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* Transformer supporting the optional chaining and nullish coalescing operators.
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*
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* Tech plan here:
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* https://github.com/alangpierce/sucrase/wiki/Sucrase-Optional-Chaining-and-Nullish-Coalescing-Technical-Plan
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*
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* The prefix and suffix code snippets are handled by TokenProcessor, and this transformer handles
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* the operators themselves.
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*/
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export default class OptionalChainingNullishTransformer extends Transformer {
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readonly tokens: TokenProcessor;
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readonly nameManager: NameManager;
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constructor(tokens: TokenProcessor, nameManager: NameManager);
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process(): boolean;
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/**
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* Determine if the current token is the last of its chain, so that we know whether it's eligible
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* to have a delete op inserted.
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*
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* We can do this by walking forward until we determine one way or another. Each
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* isOptionalChainStart token must be paired with exactly one isOptionalChainEnd token after it in
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* a nesting way, so we can track depth and walk to the end of the chain (the point where the
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* depth goes negative) and see if any other subscript token is after us in the chain.
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*/
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isLastSubscriptInChain(): boolean;
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/**
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* Determine if we are the open-paren in an expression like super.a()?.b.
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*
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* We can do this by walking backward to find the previous subscript. If that subscript was
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* preceded by a super, then we must be the subscript after it, so if this is a call expression,
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* we'll need to attach the right context.
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*/
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justSkippedSuper(): boolean;
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}
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