matchStrict proposal

[fleg]

How about strict match version? Which is exactly like match except this:

If the object and pattern are loosely equal, then pass

It would be very convenient in cases when object contains some dynamic fields, for example identificators or dates, and I don't care of it content, but rest of the fields should be matching strictly.

[isaacs]

So, I'm not sure how this actually ends up differing from t.hasStrict? Could you just use that?

[fleg]

hasStrict doesn't allow matching by class constructor, for example:

t.hasStrict(
  {
    id: 1,
    createdAt: new Date(),
    name: 'foo',
    level: 2,
    items: ['bar', 'baz'],
  },
  {
    id: Number,
    createdAt: Date,
    name: 'foo',
    level: 2,
    items: ['bar', 'baz']
  }
);

ends up with error

    not ok 1 - should contain all provided fields strictly
      ---
      diff: |
        --- expected
        +++ actual
        @@ -1,6 +1,6 @@
         Object {
        -  "id": Function Number(),
        -  "createdAt": Function Date(),
        +  "id": 1,
        +  "createdAt": 2021-02-16T15:34:51.377Z,
           "level": 2,
           "name": "foo",
           "items": Array [

match is comparing loosely, so I want this to fail

  t.matchStrict(
    {
      id: 1,
      createdAt: new Date(),
      level: 2,
      name: 'foo',
      items: ['bar', 'baz'],
    },
    {
      id: Number,
      createdAt: Date,
      level: '2', // mind the string
      name: 'foo',
      items: ['bar', 'baz']
    }
  );

and this to pass

  t.matchStrict(
    {
      id: 1,
      createdAt: new Date(),
      level: '2',
      name: 'foo',
      items: ['bar', 'baz'],
    },
    {
      id: Number,
      createdAt: Date,
      level: '2', 
      name: 'foo',
      items: ['bar', 'baz']
    }
  );

[isaacs]

"Match, but fail if (a == b) && !(a === b)" is going to be the MatchStrict implementation in the next version. In every other way, it'll be identical to Match.