TypeScript/tests/cases/fourslash/codeFixInferFromUsageNumberIndexSignature.ts

/// <reference path='fourslash.ts' />

// @noImplicitAny: true
////function f([|a |]) {
////    return a[0] + 1;
////}

verify.rangeAfterCodeFix("a: number[]",/*includeWhiteSpace*/ undefined, /*errorCode*/ undefined, 0);
Fix inferFromUsage on index signatures (#25934) * Fix inferFromUsage on index signatures 1. Check the argumentExpression to determine the index signature type. Previously, the code mistakenly checked the type of the element access itself, which never returned a good type. 2. If inference for the index signature type fails, substitute anyType. Previously, the code would create a bad index signature with an undefined type. 3. Add tests. Previously, there were no tests. * Fixing (1) means that number index signatures are now created. Previously, only string index signatures would be created. * Fixing (2) means that index signatures will be inferred from single usage like `return a[0]`. Previously, the refactoring would fail, perhaps because of a check when stringifying the index signature (I haven't tracked down why.) * Update fourslash test with improved inference 2018-07-25 19:51:11 +02:00			`/// <reference path='fourslash.ts' />`

			`// @noImplicitAny: true`
			`////function f([\|a \|]) {`
			`//// return a[0] + 1;`
			`////}`

codeFixInferFromUsage: Assume that using `x[0]` means that `x` is an array (#26739) * codeFixInferFromUsage: Assume that using `x[0]` means that `x` is an array * Remove unnecessary '\|\|' with non-falsy LHS If only there were some kind of type-checker for JavaScript that could detect this sort of thing 2018-08-29 20:37:31 +02:00			`verify.rangeAfterCodeFix("a: number[]",/includeWhiteSpace/ undefined, /errorCode/ undefined, 0);`