Get nested object property from path string

JavaScript, Object, Regexp · Oct 19, 2020

Retrieves a set of properties indicated by the given selectors from an object.

Use Array.prototype.map() for each selector, String.prototype.replace() to replace square brackets with dots.
Use String.prototype.split() to split each selector.
Use Array.prototype.filter() to remove empty values and Array.prototype.reduce() to get the value indicated by each selector.

const get = (from, ...selectors) =>
  [...selectors].map(s =>
    s
      .replace(/\[([^\[\]]*)\]/g, '.$1.')
      .split('.')
      .filter(t => t !== '')
      .reduce((prev, cur) => prev && prev[cur], from)
  );

const obj = {
  selector: { to: { val: 'val to select' } },
  target: [1, 2, { a: 'test' }],
};
get(obj, 'selector.to.val', 'target[0]', 'target[2].a');
// ['val to select', 1, 'test']

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