52a8560298
• A type guard of the form !expr o when true, narrows the type of x by expr when false, or o when false, narrows the type of x by expr when true.
108 lines
3.1 KiB
TypeScript
108 lines
3.1 KiB
TypeScript
//// [typeGuardOfFormNotExpr.ts]
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var str: string;
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var bool: boolean;
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var num: number;
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var strOrNum: string | number;
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var strOrNumOrBool: string | number | boolean;
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var numOrBool: number | boolean;
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// A type guard of the form !expr
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// - when true, narrows the type of x by expr when false, or
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// - when false, narrows the type of x by expr when true.
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// !typeguard1
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if (!(typeof strOrNum === "string")) {
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num === strOrNum; // number
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}
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else {
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str = strOrNum; // string
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}
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// !(typeguard1 || typeguard2)
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if (!(typeof strOrNumOrBool === "string" || typeof strOrNumOrBool === "number")) {
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bool = strOrNumOrBool; // boolean
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}
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else {
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strOrNum = strOrNumOrBool; // string | number
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}
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// !(typeguard1) || !(typeguard2)
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if (!(typeof strOrNumOrBool !== "string") || !(typeof strOrNumOrBool !== "number")) {
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strOrNum = strOrNumOrBool; // string | number
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}
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else {
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bool = strOrNumOrBool; // boolean
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}
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// !(typeguard1 && typeguard2)
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if (!(typeof strOrNumOrBool !== "string" && typeof strOrNumOrBool !== "number")) {
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strOrNum = strOrNumOrBool; // string | number
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}
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else {
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bool = strOrNumOrBool; // boolean
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}
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// !(typeguard1) && !(typeguard2)
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if (!(typeof strOrNumOrBool === "string") && !(typeof strOrNumOrBool === "number")) {
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bool = strOrNumOrBool; // boolean
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}
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else {
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strOrNum = strOrNumOrBool; // string | number
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}
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// !(typeguard1) && simpleExpr
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if (!(typeof strOrNumOrBool === "string") && numOrBool !== strOrNumOrBool) {
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numOrBool = strOrNumOrBool; // number | boolean
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}
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else {
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var r1: string | number | boolean = strOrNumOrBool; // string | number | boolean
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}
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//// [typeGuardOfFormNotExpr.js]
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var str;
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var bool;
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var num;
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var strOrNum;
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var strOrNumOrBool;
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var numOrBool;
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// A type guard of the form !expr
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// - when true, narrows the type of x by expr when false, or
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// - when false, narrows the type of x by expr when true.
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// !typeguard1
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if (!(typeof strOrNum === "string")) {
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num === strOrNum; // number
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}
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else {
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str = strOrNum; // string
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}
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// !(typeguard1 || typeguard2)
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if (!(typeof strOrNumOrBool === "string" || typeof strOrNumOrBool === "number")) {
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bool = strOrNumOrBool; // boolean
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}
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else {
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strOrNum = strOrNumOrBool; // string | number
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}
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// !(typeguard1) || !(typeguard2)
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if (!(typeof strOrNumOrBool !== "string") || !(typeof strOrNumOrBool !== "number")) {
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strOrNum = strOrNumOrBool; // string | number
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}
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else {
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bool = strOrNumOrBool; // boolean
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}
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// !(typeguard1 && typeguard2)
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if (!(typeof strOrNumOrBool !== "string" && typeof strOrNumOrBool !== "number")) {
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strOrNum = strOrNumOrBool; // string | number
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}
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else {
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bool = strOrNumOrBool; // boolean
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}
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// !(typeguard1) && !(typeguard2)
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if (!(typeof strOrNumOrBool === "string") && !(typeof strOrNumOrBool === "number")) {
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bool = strOrNumOrBool; // boolean
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}
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else {
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strOrNum = strOrNumOrBool; // string | number
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}
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// !(typeguard1) && simpleExpr
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if (!(typeof strOrNumOrBool === "string") && numOrBool !== strOrNumOrBool) {
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numOrBool = strOrNumOrBool; // number | boolean
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}
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else {
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var r1 = strOrNumOrBool; // string | number | boolean
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}
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