on-one/dist/esm/index.js

Subscribe to one or more events and accept the first emitted

const isArray = Array.isArray || ((x)=>Object.prototype.toString.call(x) === '[object Array]');
export default function onOne(emitter, nameOrNames, fn) {
    const names = isArray(nameOrNames) ? nameOrNames : [
        nameOrNames
    ];
    let called = false;
    const wrappers = [];
    names.forEach((name)=>{
        function wrapper(...args) {
            if (called) return;
            called = true;
            // cleanup
            for(let i = 0; i < names.length; i++){
                emitter.removeListener(names[i], wrappers[i]);
            }
            // error-first callback: 'error' event passes error as first arg, others pass null
            if (name === 'error') {
                return fn(args[0], name);
            }
            return fn(null, ...args, name);
        }
        wrappers.push(wrapper);
        emitter.on(name, wrapper);
    });
}