66 lines
1.2 KiB
TypeScript
66 lines
1.2 KiB
TypeScript
// @allowJs: true
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// @checkJs: true
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// @noEmit: true
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// @allowUnreachableCode: false
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// @filename: assertionsAndNonReturningFunctions.js
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/** @typedef {(check: boolean) => asserts check} AssertFunc */
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/** @type {AssertFunc} */
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const assert = check => {
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if (!check) throw new Error();
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}
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/** @type {(x: unknown) => asserts x is string } */
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function assertIsString(x) {
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if (!(typeof x === "string")) throw new Error();
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}
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/**
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* @param {boolean} check
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* @returns {asserts check}
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*/
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function assert2(check) {
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if (!check) throw new Error();
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}
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/**
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* @returns {never}
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*/
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function fail() {
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throw new Error();
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}
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/**
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* @param {*} x
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*/
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function f1(x) {
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if (!!true) {
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assert(typeof x === "string");
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x.length;
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}
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if (!!true) {
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assert2(typeof x === "string");
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x.length;
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}
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if (!!true) {
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assertIsString(x);
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x.length;
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}
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if (!!true) {
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fail();
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x; // Unreachable
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}
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}
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/**
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* @param {boolean} b
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*/
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function f2(b) {
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switch (b) {
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case true: return 1;
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case false: return 0;
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}
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b; // Unreachable
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}
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