Object Utilities API reference for object manipulation functions box API Reference
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Object Utilities

The Object utilities provide a set of functions for working with objects in JavaScript. These functions help in manipulating, transforming, and querying objects efficiently.

Functions

keys

function keys(obj)

Return keys from an object.

Parameters

NameTypeDescription
objobjectThe object to get keys from

Returns

An array of the object’s keys, or undefined if the input is not an object.

Example

import { keys } from '@semantic-ui/utils';
const obj = { a: 1, b: 2, c: 3 };
console.log(keys(obj)); // ['a', 'b', 'c']

values

function values(obj)

Return values from an object.

Parameters

NameTypeDescription
objobjectThe object to get values from

Returns

An array of the object’s values, or undefined if the input is not an object.

Example

import { values } from '@semantic-ui/utils';
const obj = { a: 1, b: 2, c: 3 };
console.log(values(obj)); // [1, 2, 3]

filterObject

function filterObject(obj, callback)

Filter an object based on a callback function.

Parameters

NameTypeDescription
objobjectThe object to filter
callbackfunctionThe callback function to test each key-value pair

Returns

A new object with the key-value pairs that passed the test.

Example

import { filterObject } from '@semantic-ui/utils';
const obj = { a: 1, b: 2, c: 3, d: 4 };
const result = filterObject(obj, (value) => value % 2 === 0);
console.log(result); // { b: 2, d: 4 }

mapObject

function mapObject(obj, callback)

Transform an object’s values based on a callback function.

Parameters

NameTypeDescription
objobjectThe object to transform
callbackfunctionThe callback function to transform each value

Returns

A new object with transformed values.

Example

import { mapObject } from '@semantic-ui/utils';
const obj = { a: 1, b: 2, c: 3 };
const result = mapObject(obj, (value) => value * 2);
console.log(result); // { a: 2, b: 4, c: 6 }

trackWrites

function trackWrites(value, callback, { strategy = 'auto', returnPaths = true, keyed = true, keys = ['id', '_id', 'hash', 'key'], onWrite, clone, equality } = {})

Runs a callback against a value and reports whether the callback changed it, with the changed fields as dot paths. Useful for running a user callback against a data structure and determining mutations.

Strategy - The default strategy ‘auto’ will use snapshot for small data structures and proxy for larger. Snapshot improves debugging by passing you a real copy, while proxy preserves performance at the cost of passing you a proxyObject inside your callback. Keyed paths (the default) come from the snapshot diff, so when they are wanted 'auto' yields to snapshot even for a large value — an explicit 'proxy' strategy keeps the no-clone path at the cost of positional paths.

Parameters

NameTypeDescription
valueanyThe value the callback may change
callbackfunctionReceives the value (or its tracked wrapper)
optionsobjectOptional configuration
Options
NameTypeDefaultDescription
strategystring’auto’'auto', 'snapshot', or 'proxy'
returnPathsbooleantrueReturn changed fields as dot paths. Pass false to skip collection on hot paths that only read changed
keyedbooleantrueId-address paths for keyed arrays (todos[#id].complete instead of todos.0.complete). Forces the snapshot strategy when paths are wanted, since keyed paths come from the snapshot diff. Pass false to keep the proxy’s no-clone behaviour on a large value
keysstring[]['id', '_id', 'hash', 'key']Identity fields for keyed paths, first present wins
onWritefunctionundefined(path, target, key) fires per observed write with the key path from the root. Implies the proxy strategy under 'auto', so its paths are positional
clonefunctioncloneClone used for snapshots
equalityfunctionisEqualEquality used when paths are skipped and for exotic snapshots

Returns

{ changed, paths, result } — whether the value changed, the changed fields as dot paths, and the callback’s return value.

Notes

paths is a covering set resolvable through get. The snapshot strategy reports net leaf differences via detectChanges and id-addresses keyed arrays by default (field[#id]). The proxy strategy reports the paths written (pruned so a written parent subsumes its children) and these are always positional — the proxy only sees the index a write went through. A wholesale change to a non-container value reports path ''. Under the proxy strategy the tracked wrapper is only valid inside the callback — using one after it returns throws.

Example

import { trackWrites, get } from '@semantic-ui/utils';
const doc = { meta: { count: 0 } };
const { changed, paths } = trackWrites(doc, (value) => {
value.meta.count++;
});
console.log(changed); // true
console.log(paths); // ['meta.count']
// paths resolve against the value, e.g. for state sync
paths.forEach((path) => sync(path, get(doc, path)));
// keyed paths by default — a field edit across a collection reads back per
// record, not by index, with zero configuration
const db = { todos: [{ id: 'a', complete: false }, { id: 'b', complete: false }] };
const completeAll = trackWrites(db, (d) => {
for (const todo of d.todos) { todo.complete = true; }
});
console.log(completeAll.paths); // ['todos[#a].complete', 'todos[#b].complete']
// the proxy strategy is the positional opt-out (no element identity)
trackWrites(db, mutator, { strategy: 'proxy' }); // paths like ['todos.0.complete']
// skip path collection on hot paths
trackWrites(doc, mutator, { returnPaths: false }); // { changed, result }

elementKey

function elementKey(item, keys = ['id', '_id', 'hash', 'key'])

The identity of an array element — the value of the first present field in keys, or undefined for a scalar or an object carrying none of them. The same convention as reactivity’s Signal.id and the renderer’s getItemID, and what the keyed detectChanges mode and the keyed get / set / unset grammar match on.

Parameters

NameTypeDescription
itemanyThe array element to read identity from
keysstring[]Candidate identity fields, first present wins

Returns

The identity value, or undefined when none of the fields are present.

Example

import { elementKey } from '@semantic-ui/utils';
console.log(elementKey({ id: 'a', _id: 'x' })); // 'a'
console.log(elementKey({ name: 'n' })); // undefined
console.log(elementKey({ sku: 's1' }, ['sku'])); // 's1'

detectChanges

function detectChanges(before, after, { keyed = true, keys = ['id', '_id', 'hash', 'key'] } = {})

Structural diff between two values, reported as dot paths from before to after — added (in after only), removed (in before only), and changed (in both, different values).

Parameters

NameTypeDescription
beforeanyThe value to diff from
afteranyThe value to diff to
optionsobjectOptional configuration
Options
NameTypeDefaultDescription
keyedbooleantrueDiff arrays of uniquely-keyed objects by element identity instead of by index. Pass false for the legacy positional walk
keysstring[]['id', '_id', 'hash', 'key']Identity fields a keyed element is matched on

Returns

{ added, removed, changed } — arrays of dot paths.

Notes

Objects recurse to leaf paths. Values that can’t be walked (Map, Set, Date, class instances) compare by deep equality and report their own path. Differing non-container roots report path ''.

By default, an array whose elements are each uniquely keyed (see elementKey) diffs by identity instead of position. It emits field[#identity] paths — field[#z] for a whole-element add, remove, or replace, field[#b].qty for a field change — so a prepend or reorder is one add by key, not a positional cascade of index rewrites. Any array that isn’t cleanly keyed (a scalar or unkeyed element, a duplicate key, or a key value carrying ., [, ], or a leading #) falls back to the positional walk, so an emitted keyed path always parses back through get / set / unset. Pass { keyed: false } for the legacy positional output, where arrays diff by index and a shifted array reports every moved position.

Example

import { detectChanges } from '@semantic-ui/utils';
const before = { name: 'a', temp: true, count: 1 };
const after = { name: 'b', count: 1, nickname: 'al' };
console.log(detectChanges(before, after));
// { added: ['nickname'], removed: ['temp'], changed: ['name'] }
// arrays of keyed objects diff by identity — a prepend plus an edit is one add
const cartBefore = { lineItems: [{ id: 'a', qty: 1 }, { id: 'b', qty: 1 }] };
const cartAfter = { lineItems: [{ id: 'z', qty: 9 }, { id: 'a', qty: 1 }, { id: 'b', qty: 5 }] };
console.log(detectChanges(cartBefore, cartAfter));
// { added: ['lineItems[#z]'], removed: [], changed: ['lineItems[#b].qty'] }
// scalar arrays (no element identity) fall back to the positional walk
console.log(detectChanges({ items: [1, 2, 3] }, { items: [1, 9] }));
// { added: [], removed: ['items.2'], changed: ['items.1'] }
// { keyed: false } restores the positional cascade for keyed objects too
console.log(detectChanges(cartBefore, cartAfter, { keyed: false }));
// { added: ['lineItems.2'], removed: [], changed: ['lineItems.0.id', 'lineItems.0.qty', 'lineItems.1.id'] }

extend

function extend(obj, ...sources)

Extend an object with properties from other objects, properly handling getter/setters.

Parameters

NameTypeDescription
objobjectThe target object to extend
sources…objectOne or more source objects

Returns

The extended object.

Example

import { extend } from '@semantic-ui/utils';
const obj1 = { a: 1, b: 2 };
const obj2 = { c: 3 };
const obj3 = { d: 4 };
const result = extend(obj1, obj2, obj3);
console.log(result); // { a: 1, b: 2, c: 3, d: 4 }

assignInPlace

function assignInPlace(target, source, { preserveExistingKeys = false, preserveGetters = false, returnChanged = false } = {})

Mutates the target object in place so its contents match the source, without replacing the object reference. Deletes keys not present in source (unless preserveExistingKeys is true), then assigns all source properties.

Parameters

NameTypeDescription
targetobjectThe object to update in place
sourceobjectThe object whose properties to apply
optionsobjectOptional configuration
Options
NameTypeDefaultDescription
preserveExistingKeysbooleanfalseKeep keys in target that are not in source
preserveGettersbooleanfalseSkip own getter descriptors when deleting keys not in source. Useful when target carries computed properties that shouldn’t be torn down by syncs
returnChangedbooleanfalseReturn whether any properties changed instead of the target

Returns

The mutated target object. If returnChanged is true, returns a boolean indicating whether any properties were added, removed, or changed.

Example

import { assignInPlace } from '@semantic-ui/utils';
const config = { host: 'localhost', port: 3000, debug: true };
assignInPlace(config, { host: 'production.app', port: 443 });
console.log(config); // { host: 'production.app', port: 443 } — debug removed
// Preserve existing keys
const settings = { theme: 'light', lang: 'en' };
assignInPlace(settings, { theme: 'dark', fontSize: 14 }, { preserveExistingKeys: true });
console.log(settings); // { theme: 'dark', lang: 'en', fontSize: 14 }
// Preserve computed properties
const view = { name: 'Alice' };
Object.defineProperty(view, 'greeting', { get() { return `Hi, ${this.name}`; }, enumerable: true });
assignInPlace(view, { name: 'Bob' }, { preserveGetters: true });
console.log(view.greeting); // 'Hi, Bob' — getter intact
// Detect changes
const state = { count: 5 };
assignInPlace(state, { count: 5 }, { returnChanged: true }); // false
assignInPlace(state, { count: 10 }, { returnChanged: true }); // true

deepExtend

function deepExtend(obj, ...sources, options)

Deep extends an object with properties from other sources, recursively merging nested plain objects and cloning non-plain objects.

Parameters

NameTypeDescription
objobjectThe target object to extend
sources…objectOne or more source objects to merge from
optionsobjectOptional configuration object
Options
NameTypeDefaultDescription
preserveNonCloneablebooleanfalsePreserve custom class instances instead of flattening them

Returns

The modified target object with deep merged properties.

Example

import { deepExtend } from '@semantic-ui/utils';
const target = {
user: { name: 'Alice', age: 30 },
settings: { theme: 'light' }
};
const source = {
user: { role: 'admin' },
settings: { notifications: true }
};
deepExtend(target, source);
console.log(target);
// {
// user: { name: 'Alice', age: 30, role: 'admin' },
// settings: { theme: 'light', notifications: true }
// }

pick

function pick(obj, ...keys)

Create a new object with only the specified keys from the original object.

Parameters

NameTypeDescription
objobjectThe source object
keys…stringThe keys to pick

Returns

A new object with only the specified keys.

Example

import { pick } from '@semantic-ui/utils';
const obj = { a: 1, b: 2, c: 3, d: 4 };
const result = pick(obj, 'a', 'c');
console.log(result); // { a: 1, c: 3 }

arrayFromObject

function arrayFromObject(obj)

Convert an object to an array of key-value pairs.

Parameters

NameTypeDescription
objobjectThe object to convert

Returns

An array of key-value pair objects.

Example

import { arrayFromObject } from '@semantic-ui/utils';
const obj = { a: 1, b: 2, c: 3 };
const result = arrayFromObject(obj);
console.log(result); // [{ key: 'a', value: 1 }, { key: 'b', value: 2 }, { key: 'c', value: 3 }]

get

function get(obj, path = '', keys = ['id', '_id', 'hash', 'key'])

Access a nested object field from a string path, like ‘a.b.c’.

Parameters

NameTypeDescription
objobjectThe object to access
pathstringThe path to the desired property
keysstring[]Identity fields for keyed [#id] segments

Returns

The value at the specified path, or undefined if not found.

Notes

A bracket segment whose body starts with # selects an array element by identity (items[#id]) rather than by position (items[0]). Identity is matched String-coerced (a number id of 7 matches [#7]), see elementKey. Returns the element when the path ends at the key, or undefined when no element matches.

Example

import { get } from '@semantic-ui/utils';
const obj = { a: { b: { c: 42 } } };
console.log(get(obj, 'a.b.c')); // 42
console.log(get(obj, 'a.b.d')); // undefined
const doc = { items: [{ id: 'a', n: 1 }, { id: 'b', n: 2 }] };
console.log(get(doc, 'items[#b].n')); // 2 (selected by identity, not position)

set

function set(obj, path, value, keys = ['id', '_id', 'hash', 'key'])

Set a nested object field from a string path, the write twin of get. Creates missing intermediates — arrays when the next segment is a numeric index, objects otherwise.

Parameters

NameTypeDescription
objobjectThe object to write into
pathstringThe path string (e.g., ‘a.b.c’, ‘items.0.name’, ‘items[0].name’, or ‘items[#id]‘)
valueanyThe value to set at the path
keysstring[]Identity fields for keyed [#id] segments

Returns

The same object reference.

Notes

Paths from trackWrites and detectChanges apply back directly. Prototype-climbing segments (__proto__, constructor, prototype) are refused, and a non-string or empty path is a no-op.

A [#id] segment addresses an array element by identity (see elementKey): a present key replaces the element in place (or writes the field through it), an absent key appends a new element (a field write through an absent key is a no-op). The prototype-pollution guard is intentionally not extended to keyed bodies — a [#__proto__] value is only ===-compared against element identities, it is never used as a property name, so it appends an inert element rather than touching Object.prototype.

Example

import { set, get, trackWrites } from '@semantic-ui/utils';
console.log(set({}, 'a.b.c', 1)); // { a: { b: { c: 1 } } }
console.log(set({}, 'items.0.name', 'first')); // { items: [{ name: 'first' }] }
// sync changes between objects
const { paths } = trackWrites(source, mutator);
paths.forEach((path) => set(replica, path, get(source, path)));
// keyed addressing — replace by identity, append when absent
const doc = { items: [{ id: 'a', n: 1 }] };
set(doc, 'items[#a]', { id: 'a', n: 100 }); // replaces in place
set(doc, 'items[#b]', { id: 'b', n: 2 }); // appends, no element had id 'b'

unset

function unset(obj, path, keys = ['id', '_id', 'hash', 'key'])

Remove a nested object field from a string path, the delete twin of get and set.

Parameters

NameTypeDescription
objobjectThe object to remove from
pathstringThe path string (e.g., ‘a.b.c’, ‘items.0’, or ‘items[#id]‘)
keysstring[]Identity fields for keyed [#id] segments

Returns

The same object reference.

Notes

A missing path is a no-op. A removed array index leaves a hole rather than splicing, so sibling index paths stay valid when applying several removals at once. Prototype-climbing segments (__proto__, constructor, prototype) are refused. Pairs with detectChanges — apply removed paths with unset and the rest with set.

A [#id] segment removes the matched array element by identity (see elementKey), splicing it out — there are no sibling index paths to keep valid, so the splice is safe.

Example

import { unset, set, get, detectChanges } from '@semantic-ui/utils';
const obj = { a: { b: 1, c: 2 } };
unset(obj, 'a.b');
console.log(obj); // { a: { c: 2 } }
// apply a full diff
const diff = detectChanges(before, after);
[...diff.added, ...diff.changed].forEach((path) => set(replica, path, get(after, path)));
diff.removed.forEach((path) => unset(replica, path));

proxyObject

function proxyObject(sourceObj = noop, referenceObj = {})

Create a proxy object that combines properties from a source object and a reference object.

Parameters

NameTypeDescription
sourceObjfunctionA function that returns the source object
referenceObjobjectThe reference object

Returns

A proxy object combining properties from both objects.

Example

import { proxyObject } from '@semantic-ui/utils';
const source = () => ({ a: 1, b: 2 });
const reference = { c: 3 };
const proxy = proxyObject(source, reference);
console.log(proxy.a); // 1
console.log(proxy.c); // 3

onlyKeys

function onlyKeys(obj, keysToKeep)

Create a new object with only the specified keys from the original object.

Parameters

NameTypeDescription
objobjectThe source object
keysToKeeparrayThe keys to keep in the new object

Returns

A new object with only the specified keys.

Example

import { onlyKeys } from '@semantic-ui/utils';
const obj = { a: 1, b: 2, c: 3, d: 4 };
const result = onlyKeys(obj, ['a', 'c']);
console.log(result); // { a: 1, c: 3 }

hasProperty

function hasProperty(obj, prop)

Check if an object has a non-inherited property.

Parameters

NameTypeDescription
objobjectThe object to check
propstringThe property name to check for

Returns

True if the object has the property, false otherwise.

Example

import { hasProperty } from '@semantic-ui/utils';
const obj = { a: 1, b: 2 };
console.log(hasProperty(obj, 'a')); // true
console.log(hasProperty(obj, 'toString')); // false

reverseKeys

function reverseKeys(obj)

Reverse the keys and values of an object.

Parameters

NameTypeDescription
objobjectThe object to reverse

Returns

A new object with reversed keys and values.

Example

import { reverseKeys } from '@semantic-ui/utils';
const obj = { a: '1', b: ['2', '3'] };
const result = reverseKeys(obj);
console.log(result); // { '1': 'a', '2': 'b', '3': 'b' }

These object utilities provide a robust set of tools for working with objects in JavaScript, enhancing productivity and code readability.

Performs a weighted search across an array of objects, with matches prioritized by where they occur in the text.

Search Priority Results are sorted by match quality, with highest priority given to exact start of string matches (e.g., searching “cat” matching “category”), followed by word-start matches (e.g., “category” in “my category”), then substring matches anywhere, and finally partial word matches. When searching multiple words, matches are weighted by how many words were found in the text.

Parameters

NameTypeDescription
querystringThe search query
objectArrayarrayArray of objects to search
optionsobjectSearch configuration
Options
NameTypeDefaultDescription
returnMatchesbooleanfalseInclude match details in results
matchAllWordsbooleantrueRequire all words to match
propertiesToMatcharray[]Properties to search within objects

Understanding Matches When returnMatches is true, each result is a spread copy of the original object with an added matches array property. The original objects are never mutated. Each match has the shape { field, type, score, value } where type is one of 'startsWith', 'wordStartsWith', 'anywhere', or 'anyWord'.

Returns

Array of matching objects sorted by relevance. When returnMatches is true, each result is a shallow copy with an additional matches property containing an array of match details.

Example

import { weightedObjectSearch } from '@semantic-ui/utils';
const items = [
{ title: 'Hello World', desc: 'A greeting' },
{ title: 'World News', desc: 'Current events' }
];
// Basic search
const results = weightedObjectSearch('world', items, {
propertiesToMatch: ['title', 'desc']
});
// With match details (does not mutate originals)
const detailed = weightedObjectSearch('world', items, {
propertiesToMatch: ['title', 'desc'],
returnMatches: true,
});
// detailed[0].matches → [{ field: 'title', type: 'startsWith', score: 1, value: 'World News' }]
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