b12-archive/is-subset

Check if an object is contained within another one

     

is-subset

Check if an object is contained within another one.

Installation

$ npm install is-subset

Usage

1. Import the module:

import isSubset from 'is-subset/module';

// …or:
var isSubset = require('is-subset');

2. These are true:

isSubset(
  {a: 1, b: 2},
  {a: 1}
);

isSubset(
  {a: 1, b: {c: 3, d: 4}, e: 5},
  {a: 1, b: {c: 3}}
);

isSubset(
  {a: 1, bcd: [1, 2, 3]},
  {a: 1, bcd: [1, 2]}
);

…and these are false:

isSubset(
  {a: 1},
  {a: 2}
);

isSubset(
  {a: 1},
  {a: 1, b: 2}
);

isSubset(
  {a: 1, bcd: [1, 2, 3]},
  {a: 1, bcd: [1, 3]}
);

See the specs for more info.

API

isSubset(superset, subset)

Check if an object is contained within another object.

Returns true if:

• all enumerable keys of subset are also enumerable in superset, and
• every value assigned to an enumerable key of subset strictly equals the value assigned to the same key of superset – or is a subset of it.

Parameters:

• Object superset
• Object subset

Return value:

• Boolean

License

MIT © Studio B12 GmbH

is-subset's Issues

is-subset always returns true for date values

For values that are dates is-subset will ignore the values and return true when the dates are different.

For example:

is-subset(
    { date, new Date(0)}
    { date, new Date()}
)

will return true even though the dates are different. Looking at the code this is because Object.keys() for a Date will return an empty array.

Something like

  if (
    superset instanceof Date && subset instanceof Date
  ) return superset.valueOf() === subset.valueOf();

after the typeof object check should fix it. I started trying to fix the issue but couldn't get any of the tests to run - getting TypeError: undefined is not a function for each test.

Measure coverage with istanbul

Isparta doesn’t do the job: https://travis-ci.org/studio-b12/is-subset/jobs/83377581. We should measure coverage with the proven istanbul on the transpiled code like we do in https://github.com/studio-b12/tape-css.

isSubset returns false when a child array's component is of a different order

It returns false on the following case, where it should've been true.

SUPERSET:
[ { id: 1,
short_name: 'apple',
long_name: 'pen pinapple apple pen',
picture_urls: [ 'fake url 1a', 'fake url 1b' ] },
{ id: 2,
short_name: 'banana',
long_name: 'cavendish banana',
picture_urls: [ 'fake url 2b', 'fake url 2a' ] } ]

SUBSET:
[ { short_name: 'apple',
long_name: 'pen pinapple apple pen',
picture_urls: [ 'fake url 1a', 'fake url 1b' ] },
{ short_name: 'banana',
long_name: 'cavendish banana',
picture_urls: [ 'fake url 2a', 'fake url 2b' ] } ]

Shallow variant

Would it be possible to get a flag or variant of this which doesn't work recursively? Specifically, from the examples in the README, the following to be false, not true:

isSubset(
  {a: 1, bcd: [1, 2, 3]},
  {a: 1, bcd: [1, 2]}
);

I.e. false because the value (the array) of bcd is not equal.

Decide on the final API

There seems to be some disagreement in the community as to where data should land.

1. Some say data should come last. Not without reason.
2. There’s a new function bind proposal which can result in very elegant code. There seems to be a lot of excitement about that.
3. At the moment we have traditional here – data as the first parameter.

Should we keep it this way (3)? Should we go with the flow (2)? Should we perhaps allow different APIs for different purposes?

const isSubset = require('is-subset/data-last');     // 1
const isSubset = require('is-subset/data-as-this');  // 2
const isSubset = require('is-subset');               // 3

I hope for some discussion here :)

Empty arrays returns true when compared to a non-empty array.

let superset = {
shoes: [41, 42] 
}

let subset = {
shoes: []
}
isSubset(superset, subset)

I think this should return false.

Add a changelog