When using '==' to compare a string and number for equality,
const a = '1234';
const b = 1234;
// The condition will always return 'false' due to the mismatched types of 'string' and 'number'.
const c = a == b;
TypeScript raises an error: This condition will always return 'false' since the types 'string' and 'number' have no overlap.
However, it works in JavaScript;
Is there any way to remove the error without using the Number function for conversion?
When comparing two values that are recognized as a string and a number by the compiler using the equality operator (==), it will always result in an error. To avoid this, you can either utilize a type assertion on one of the values or employ an abstraction for comparison, like the function demonstrated below:
function areEqual (a: unknown, b: unknown): boolean {
return a == b;
}
const a = '1234';
const b = 1234;
let c: boolean;
c = a == b; /*
~~~~~~
This condition will always return 'false' since the types 'string' and 'number' have no overlap.(2367) */
c = areEqual(a, b); // ok
c = a as unknown == b; // ok
If the compiler is uncertain about whether the values are definitely a string and a number, there won't be an issue with directly comparing them:
let a = '1234' as string | number;
let b = 1234 as string | number;
const c = a == b; // ok
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