Transformation API Cleanup #11165
Transformation API Cleanup #11165
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| * | ||
| * If the token's end position is synthetic (undefined or a negative value), no mapping | ||
| * will be created. | ||
| * Emits a token of a node node with possible leading and trailing source maps. |
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Emits a token of a node ... instead of Emits a token of a node node ...
| * | ||
| * NOTE: Do not call this method directly. It is part of the emit pipeline | ||
| * and should only be called indirectly from pipelineEmitWithSourceMap or | ||
| * pipelineEmitInUnspecifiedContext (when pickign a more specific context). |
| @@ -2798,6 +2798,20 @@ namespace ts { | |||
| return tokenSourceMapRanges && tokenSourceMapRanges[token]; | |||
| } | |||
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| export function getConstantValue(node: Node) { | |||
| const emitNode = node.emitNode; | |||
| if (emitNode && emitNode.flags & EmitFlags.ConstantValue) { | |||
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q: why can't you just check if there exists emitNode.constantValue instead of using the EmitFlags.ConstatntValue
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It probably doesn't matter. Since constantValue is an expando property, I was trying to avoid some deoptimization cases.
| @@ -23,15 +23,15 @@ let c1 = Foo["C"].toString(); | |||
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| //// [constEnumToStringWithComments.js] | |||
| var x0 = 100 /* X */..toString(); | |||
| var x1 = 100 /* "X" */..toString(); | |||
| var x0 = 100 /* X */.toString(); | |||
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q: why one of the "." is gone? Also realize that space after number is important 😅
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We should only ever emit .. if the preceding text is an integer literal. We do not need to emit .. if the preceding text is a decimal literal, whitespace, a comment, or anything else. 100/**/..toString() is not legal JavaScript, so the previous outcome for this test was invalid.
| @@ -5,7 +5,7 @@ namespace ts { | |||
| export interface CommentWriter { | |||
| reset(): void; | |||
| setSourceFile(sourceFile: SourceFile): void; | |||
| emitNodeWithComments(node: Node, emitCallback: (node: Node) => void): void; | |||
| emitNodeWithComments(emitContext: EmitContext, node: Node, emitCallback: (emitContext: EmitContext, node: Node) => void): void; | |||
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at first it is a bit confusing with emitContext and context which is a TransformationContext
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I'm open to a better name, but I feel this is the correct terminology.
This PR cleans up and improves the design of the transformer and pretty printer, and reduces the overall size of
Node. Notable changes include:emitFlags,sourceMapRange, andcommentRangetoEmitNodeobject.Nodeand seems to reduce the total memory used by 5-8MB (based on the "Memory Used" statistic as part of our performance tests.getNodeEmitFlags,setNodeEmitFlags, etc. out oftransformer.tstofactory.ts.emitter.ts.emitNodeWithSourceMapsintosourcemaps.ts.emitNodeWithNotificationintotransformer.ts.trySubstituteNodeintotransformer.ts(asemitNodeWithSubstitution).tryEmitConstantValueintots.tsas part of substitution.sourcemap.tschainandcomposefromtransformer.tstocore.tsIn addition to the aforementioned reduction in memory footprint, this results in a small performance improvement in overall compiler time for most scenarios (between 0.6% to 1.5% improvement).