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=== tests/cases/conformance/expressions/typeGuards/typeGuardsInRightOperandOfAndAndOperator.ts ===
// In the right operand of a && operation,
// the type of a variable or parameter is narrowed by any type guard in the left operand when true.
function foo(x: number | string) {
>foo : (x: number | string) => boolean
>x : string | number
return typeof x === "string" && x.length === 10; // string
>typeof x === "string" && x.length === 10 : boolean
>typeof x === "string" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : string | number
>"string" : "string"
>x.length === 10 : boolean
>x.length : number
>x : string
>length : number
>10 : 10
}
function foo2(x: number | string) {
>foo2 : (x: number | string) => number
>x : string | number
// modify x in right hand operand
return typeof x === "string" && ((x = 10) && x); // string | number
>typeof x === "string" && ((x = 10) && x) : number
>typeof x === "string" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : string | number
>"string" : "string"
>((x = 10) && x) : number
>(x = 10) && x : number
>(x = 10) : 10
>x = 10 : 10
>x : string | number
>10 : 10
>x : number
}
function foo3(x: number | string) {
>foo3 : (x: number | string) => string
>x : string | number
// modify x in right hand operand with string type itself
return typeof x === "string" && ((x = "hello") && x); // string | number
>typeof x === "string" && ((x = "hello") && x) : string
>typeof x === "string" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : string | number
>"string" : "string"
>((x = "hello") && x) : string
>(x = "hello") && x : string
>(x = "hello") : "hello"
>x = "hello" : "hello"
>x : string | number
>"hello" : "hello"
>x : string
}
function foo4(x: number | string | boolean) {
>foo4 : (x: number | string | boolean) => boolean
>x : string | number | boolean
return typeof x !== "string" // string | number | boolean
>typeof x !== "string" // string | number | boolean && typeof x !== "number" // number | boolean && x : boolean
>typeof x !== "string" // string | number | boolean && typeof x !== "number" : boolean
>typeof x !== "string" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : string | number | boolean
>"string" : "string"
&& typeof x !== "number" // number | boolean
>typeof x !== "number" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : number | boolean
>"number" : "number"
&& x; // boolean
>x : boolean
}
function foo5(x: number | string | boolean) {
>foo5 : (x: number | string | boolean) => boolean
>x : string | number | boolean
// usage of x or assignment to separate variable shouldn't cause narrowing of type to stop
var b: number | boolean;
>b : number | boolean
return typeof x !== "string" // string | number | boolean
>typeof x !== "string" // string | number | boolean && ((b = x) && (typeof x !== "number" // number | boolean && x)) : boolean
>typeof x !== "string" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : string | number | boolean
>"string" : "string"
&& ((b = x) && (typeof x !== "number" // number | boolean
>((b = x) && (typeof x !== "number" // number | boolean && x)) : boolean
>(b = x) && (typeof x !== "number" // number | boolean && x) : boolean
>(b = x) : number | boolean
>b = x : number | boolean
>b : number | boolean
>x : number | boolean
>(typeof x !== "number" // number | boolean && x) : boolean
>typeof x !== "number" // number | boolean && x : boolean
>typeof x !== "number" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : number | true
>"number" : "number"
&& x)); // boolean
>x : true
}
function foo6(x: number | string | boolean) {
>foo6 : (x: number | string | boolean) => boolean
>x : string | number | boolean
// Mixing typeguard narrowing in if statement with conditional expression typeguard
return typeof x !== "string" // string | number | boolean
>typeof x !== "string" // string | number | boolean && (typeof x !== "number" // number | boolean ? x // boolean : x === 10) : boolean
>typeof x !== "string" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : string | number | boolean
>"string" : "string"
&& (typeof x !== "number" // number | boolean
>(typeof x !== "number" // number | boolean ? x // boolean : x === 10) : boolean
>typeof x !== "number" // number | boolean ? x // boolean : x === 10 : boolean
>typeof x !== "number" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : number | boolean
>"number" : "number"
? x // boolean
>x : boolean
: x === 10) // number
>x === 10 : boolean
>x : number
>10 : 10
}
function foo7(x: number | string | boolean) {
>foo7 : (x: number | string | boolean) => string
>x : string | number | boolean
var y: number| boolean | string;
>y : string | number | boolean
var z: number| boolean | string;
>z : string | number | boolean
// Mixing typeguard narrowing
return typeof x !== "string"
>typeof x !== "string" && ((z = x) // number | boolean && (typeof x === "number" // change value of x ? ((x = 10) && x.toString()) // x is number // do not change value : ((y = x) && x.toString()))) : string
>typeof x !== "string" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : string | number | boolean
>"string" : "string"
&& ((z = x) // number | boolean
>((z = x) // number | boolean && (typeof x === "number" // change value of x ? ((x = 10) && x.toString()) // x is number // do not change value : ((y = x) && x.toString()))) : string
>(z = x) // number | boolean && (typeof x === "number" // change value of x ? ((x = 10) && x.toString()) // x is number // do not change value : ((y = x) && x.toString())) : string
>(z = x) : number | boolean
>z = x : number | boolean
>z : string | number | boolean
>x : number | boolean
&& (typeof x === "number"
>(typeof x === "number" // change value of x ? ((x = 10) && x.toString()) // x is number // do not change value : ((y = x) && x.toString())) : string
>typeof x === "number" // change value of x ? ((x = 10) && x.toString()) // x is number // do not change value : ((y = x) && x.toString()) : string
>typeof x === "number" : boolean
>typeof x : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
>x : number | true
>"number" : "number"
// change value of x
? ((x = 10) && x.toString()) // x is number
>((x = 10) && x.toString()) : string
>(x = 10) && x.toString() : string
>(x = 10) : 10
>x = 10 : 10
>x : string | number | boolean
>10 : 10
>x.toString() : string
>x.toString : (radix?: number) => string
>x : number
>toString : (radix?: number) => string
// do not change value
: ((y = x) && x.toString()))); // x is boolean
>((y = x) && x.toString()) : string
>(y = x) && x.toString() : string
>(y = x) : true
>y = x : true
>y : string | number | boolean
>x : true
>x.toString() : string
>x.toString : () => string
>x : true
>toString : () => string
}
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