getPathValue() function for deep objects

Question

This is a follow-up question to this: getPathValue() function for deep objects with arrays and with packed JSON

The accepted answer works very well in most situations:

Answer 1

Change:

.split('.')

By:

.split('.').filter(Boolean)

It will remedy a dot that got placed at the very beginning of the string, which is what happens when the input starts with a [, like in [0].

Demo:

function getPathValue(object, path) {
    return path
       .replace(/\[/g, '.')
       .replace(/\]/g, '')
       .split('.').filter(Boolean)
       .reduce(function (o, k) {
           return (typeof o === 'string' ? JSON.parse(o) : (o || {}))[k];
       }, object);
}

var obj = [{"currencyPair":"EUR/USD","timestamp":"1546028298698","bidBig":"1.14","bidPips":"450","offerBig":"1.14","offerPips":"457","high":"1.14253","low":"1.14732","open":"1.14305"},{"currencyPair":"USD/JPY","timestamp":"1546028299095","bidBig":"110.","bidPips":"326","offerBig":"110.","offerPips":"336","high":"110.222","low":"111.062","open":"111.012"}];

value = getPathValue(obj, '[0].bidPips');

console.log(value);

It can be done easier though, by replacing the replace and split calls by one match call:

function getPathValue(object, path) {
    return path
       .match(/[^[\].]+/g)
       .reduce(function (o, k) {
           return (typeof o === 'string' ? JSON.parse(o) : (o || {}))[k];
       }, object);
}

var obj = [{"currencyPair":"EUR/USD","timestamp":"1546028298698","bidBig":"1.14","bidPips":"450","offerBig":"1.14","offerPips":"457","high":"1.14253","low":"1.14732","open":"1.14305"},{"currencyPair":"USD/JPY","timestamp":"1546028299095","bidBig":"110.","bidPips":"326","offerBig":"110.","offerPips":"336","high":"110.222","low":"111.062","open":"111.012"}];
value = getPathValue(obj, '[0].bidPips');

console.log(value);