Minify some Logical Expression patterns #227
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This looks awesome @boopathi |
| @@ -124,6 +124,54 @@ module.exports = ({ types: t }) => { | |||
| ], | |||
| }, | |||
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| LogicalExpression(path) { | |||
| const left = path.get("left"); | |||
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nit: declarations can be moved closer to usage.
| }; | ||
| const FALSY = (input) => { | ||
| // NaN and undefined are falsy | ||
| if (input.isIdentifier()) { |
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Is this needed because the .isPure() method doesn't work for NaN and undefined yet, since !undefined and !NaN are true? Are there any other such special instances?
| if (result.match) { | ||
| // here we are sure that left.evaluate is always confident becuase | ||
| // it satisfied one of TRUTHY/FALSY paths | ||
| path.replaceWith(result.value(t.valueToNode(left.evaluate().value), right.node)); |
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Would it be worth caching/re-using the result of left.evaluate()? I don't know how expensive these evaluations generally are.
| @@ -124,6 +124,54 @@ module.exports = ({ types: t }) => { | |||
| ], | |||
| }, | |||
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| LogicalExpression(path) { | |||
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It feels these simplifications should be done in a post-order traversal (i.e. on exit) -- does this resolve properly for nested conditions?
e.g. (3 || foo()) || bar() should simplify to just 3.
| expect(transform(sources[i])).toBe(sources[i]); | ||
| } | ||
| }); | ||
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test cases for nested logical expressions?
boopathi
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