How to skip over an element in .map()?

Question

How can I skip an array element in .map?

My code:

var sources = images.map(function (img) {
    if(img.src.split(\'.\').pop() === \"json         


        

Answer 1

Here's a fun solution:

/**
 * Filter-map. Like map, but skips undefined values.
 *
 * @param callback
 */
function fmap(callback) {
    return this.reduce((accum, ...args) => {
        let x = callback(...args);
        if(x !== undefined) {
            accum.push(x);
        }
        return accum;
    }, []);
}

Use with the bind operator:

[1,2,-1,3]::fmap(x => x > 0 ? x * 2 : undefined); // [2,4,6]