A tiny (173B) utility to flatten an object with customizable glue

This module squashes a nested object (including its internal Arrays) so that the output is a flat object – AKA, it has a single level of depth. By default, the _ character is used to glue/join layers' keys together. This is customizable, of course.

Finally, any keys with nullish values (null and undefined) are not included in the return object.

$ npm install --save flat-obj

import flatObj from 'flat-obj';

flatObj({
  a: 'hi',
  b: {
    a: null,
    b: '',
    d: 'hello',
    e: {
      a: 'yo',
      b: undefined,
      c: 'sup',
      d: 0
    }
  },
  c: 'world'
});
//=> { a:'hi', b_b:'', b_d:'hello', b_e_a:'yo', b_e_c:'sup', b_e_d:0, c:'world' }

Note: null and undefined values are purged.

Returns: Object

Returns a new object with a single level of depth.

Type: Object

The object to flatten.

Type: String
Default: _

A string used to join parent key names to nested child key names.

const foo = { bar: 123 };

flatObj({ foo }); //=> { foo_bar: 123 }
flatObj({ foo }, '.'); //=> { 'foo.bar': 123 }

Running on Node.js v10.13.0

Validation:
  ✔ flat
  ✔ flatten-object
  ✔ [email protected]
  ✔ flat-obj

Benchmark:
  flat               x 187,778 ops/sec ±1.27% (87 runs sampled)
  flatten-object     x 191,514 ops/sec ±0.26% (93 runs sampled)
  [email protected]       x 268,060 ops/sec ±1.21% (94 runs sampled)
  flat-obj           x 622,744 ops/sec ±0.33% (92 runs sampled)

MIT © Luke Edwards