61 lines
1.4 KiB
TypeScript
61 lines
1.4 KiB
TypeScript
// @strictNullChecks: true
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// @declaration: true
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function f(addUndefined1 = "J", addUndefined2?: number) {
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return addUndefined1.length + (addUndefined2 || 0);
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}
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function g(addUndefined = "J", addDefined: number) {
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return addUndefined.length + addDefined;
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}
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let total = f() + f('a', 1) + f('b') + f(undefined, 2);
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total = g('c', 3) + g(undefined, 4);
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function foo1(x: string = "string", b: number) {
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x.length;
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}
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function foo2(x = "string", b: number) {
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x.length; // ok, should be string
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}
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function foo3(x: string | undefined = "string", b: number) {
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x.length; // ok, should be string
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x = undefined;
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}
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function foo4(x: string | undefined = undefined, b: number) {
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x; // should be string | undefined
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x = undefined;
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}
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type OptionalNullableString = string | null | undefined;
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function allowsNull(val: OptionalNullableString = "") {
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val = null;
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val = 'string and null are both ok';
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}
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allowsNull(null); // still allows passing null
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// .d.ts should have `string | undefined` for foo1, foo2, foo3 and foo4
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foo1(undefined, 1);
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foo2(undefined, 1);
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foo3(undefined, 1);
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foo4(undefined, 1);
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function removeUndefinedButNotFalse(x = true) {
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if (x === false) {
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return x;
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}
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}
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declare const cond: boolean;
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function removeNothing(y = cond ? true : undefined) {
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if (y !== undefined) {
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if (y === false) {
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return y;
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}
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}
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return true;
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}
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