objtools

objtools

objtools provides several utility functions for working with structured objects. Basic examples of how to use are provided below. See the docs directory for full information.

Utility Functions

var objtools = require('objtools');

// Check whether a value should be treated as a scalar entity
objtools.isScalar(val)

// Faster equivalents to lodash
objtools.isPlainObject(val)
objtools.isEmpty(val)

// Faster type-specific isEmpty variants
objtools.isEmptyObject(val)
objtools.isEmptyArray(val)

// Check whether two objects deeply equal each other
objtools.deepEquals(a, b)

// Check whether two scalars equal each other (mostly equivalent to ===)
// but handles dates
objtools.scalarEquals(a, b)

// Make a duplicate of an object without references to the original
objtools.deepCopy(obj)

// Given an object, create a mapping from dotted paths to values
objtools.collapseToDotted({
	foo: {
		bar: {
			baz: 123
		}
	}
})
// -> { 'foo.bar.baz': 123 }
// Has additional options, see docs directory for details

// Checks if all fields in the query match corresponding fields in
// the dotted object
objtools.matchDottedObject({ 'foo.bar': 123, baz: 456 }, { 'foo.bar': 123 } )

// Checks if all fields in the query match corresponding fields in
// the object
objtools.matchObject( { foo: { bar: 123} }, { 'foo.bar': 123 } );

// Update the destination object in-place to match the source object.  This
// also takes a third argument of hooks to register while traversing.  See
// the docs for details.
objtools.syncObject( { /* destination object */ }, { /* source object */ } );

// Recursively merge source objects into a base object
objtools.merge(
	{ 'characters': [ { 'name': 'barney' }, { 'name': 'fred' } ] },
	{ 'characters': [ { 'age': 36 }, { 'age': 40 } ] },
	{ 'characters': [ { 'height': '5\'4"' }, { 'height': '5\'5"' } ] }
)
// => { 'characters': [
//			{ 'name': 'barney', 'age': 36, 'height': '5\'4"' },
//			{ 'name': 'fred', 'age': 40, 'height': '5\'5"' }
// ] }

// Get duplicates in an array
objtools.getDuplicates([ 'a', 'b', 'a', 'c', 'c' ]);
// => [ 'a', 'c' ];

// Get a structured diff of collections
objtools.diffObjects({
	a: 'b', c: 'd', e: 'f', g: 'h',
	i: { j: 'k' },
	l: { m: 'n', o: { p: 'q' } }
}, {
	a: 'b', c: 1, e: 'f',
	g: { h: true },
	i: { k: 'j' },
	l: { m: 'nop' }
})
// => {
//		c: [ 'd', 1 ],
//		g: [ 'h', { h: true } ],
//		i: [ { j: 'k' }, { k: 'j' } ],
//		l: {
//			m: [ 'n', 'nop' ],
//			o: [ { p: 'q' }, null ]
//		}
//	};

// Get a structured diff of objects and scalars
const result = objtools.diffObjects({
	a: 'b', c: 'd', e: 'f', g: 'h',
	i: { j: 'k' },
	l: { m: 'n', o: { p: 'q' } }
}, {
	a: 'b', c: 1, e: 'f',
	g: { h: true },
	i: { k: 'j' },
	l: { m: 'nop' }
}, 'scalar');

const expected = _.extend([ null, null, 'scalar' ], {
	a: [ 'b', 'b', null ],
	c: [ 'd', 1, null ],
	e: [ 'f', 'f', null ],
	g: [ 'h', { h: true }, null ],
	i: [ { j: 'k' }, { k: 'j' }, null ],
	l: {
		m: [ 'n', 'nop', null ],
		o: [ { p: 'q' }, null, null ]
	}
});
_.isEqual(result, expected);
// => true

// Get a consistent hash of an object or primitive which is unlikely to conflict with other objects
const obj = { a: 1, b: '2' };
let hash = objtools.objectHash(obj);  // Long hex string

Path Functions

These functions involve "object paths". An object path is a dot-separated key specifying a field in an object. For example, in this object:

var obj = {
	foo: {
		bar: [
			1,
			2,
			3
		]
	}
};

The path to 2 is foo.bar.1 .

Examples of the path functions:

objtools.getPath(obj, 'foo.bar.1');		// gets 2
objtools.setPath(obj, 'foo.biz', 4);	// equivalent to obj.foo.biz = 4
objtools.deletePath(obj, 'foo.biz');	// equivalent to delete obj.foo.biz
objtools.dottedDiff({									// returns an array of the shortest diff paths
	a: { b: 'c', d: { e: 'f' } },
	d: 'efg'
}, {
	a: { b: 'c', d: true },
	d: 'e',
	f: 'g'
});
// => [ 'a.d', 'd', 'f' ];

Masks

A "mask" is a structured mapping from keys to boolean true. For example, take this object:

{
	foo: {
		bar: {
			baz: 12,
			biz: 'test123',
			buz: 'bip'
		}
	}
}

A mask that matches only the biz field would be:

{
	foo: {
		bar: {
			biz: true
		}
	}
}

A mask that matches anything inside the bar object would be:

{
	foo: {
		bar: true
	}
}

A mask that matches all fields is simply true, whereas a mask that matches no fields is false.

Masks can also contain wildcards. For example, a mask that matches everything in the bar object except for baz is:

{
	foo: {
		bar: {
			_: true,
			baz: false
		}
	}
}

Arrays can also be used as aliases for wildcards. They are converted to underscore wildcards on instantiation. These two masks are equivalent:

{ _: { foo: true, bar: true } }
[ { foo: true, bar: true } ]

These are some of the functions that can be performed on masks. See the docs directory for details. This is not a complete list.

var ObjectMask = require('objtools').ObjectMask;

// Create a mask
var mask = new ObjectMask({
	foo: true,
	bar: {
		biz: {
			buz: true
		}
	}
});

// Filter an object by the mask
// Takes additional options, see docs for details
mask.filterObject(obj)

// Get a subcomponent of a mask
mask.getSubMask('bar.biz')	// { buz: true }

// Check to see if the mask allows a given path
mask.checkPath('bar.biz.buz')

// Convert an ObjectMask object back into a plain object
mask.toObject()

// Validate a mask according to strict rules (only objects, arrays, and booleans)
mask.validate()

// List all fields in an object restricted by a mask
mask.getMaskedOutFields(obj)

// Returns true if all fields in the object are allowed by the mask
mask.checkFields(obj)

// Combine two or more masks such that the resulting mask matches everything that either
// of the source masks match (ie, a logical OR)
ObjectMask.addMasks(mask, mask2, ...)

// Combine two or more masks such that the result mask matches only what ALL of the
// source masks match (ie, a logical AND)
ObjectMask.andMasks(mask, mask2, ...)

// Invert a mask (new mask matches all unmatched paths, doesn't match all matched paths)
// Similar to logical 'not'
ObjectMask.invertMask(mask);