Function and

You can think of this like a short-circuiting logical "and" operation on a Result type. If result is Ok, then the result is the andResult. If result is Err, the result is the Err.

This is useful when you have another Result value you want to provide if and only if you have an Ok – that is, when you need to make sure that if you Err, whatever else you're handing a Result to also gets that Err.

Notice that, unlike in map or its variants, the original result is not involved in constructing the new Result.

Examples

import { and, ok, err, toString } from 'true-myth/result';

const okA = ok('A');
const okB = ok('B');
const anErr = err({ so: 'bad' });

console.log(toString(and(okB, okA)));  // Ok(B)
console.log(toString(and(okB, anErr)));  // Err([object Object])
console.log(toString(and(anErr, okA)));  // Err([object Object])
console.log(toString(and(anErr, anErr)));  // Err([object Object])
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Typeparam

T The type of the value wrapped in the Ok of the Result.

Typeparam

U The type of the value wrapped in the Ok of the andResult, i.e. the success type of the Result present if the checked Result is Ok.

Typeparam

E The type of the value wrapped in the Err of the Result.