A collection of functions to perform immutable operations on plain JavaScript objects and arrays.
Like updeep but with batched mutations and no freezing.
Like icepick, but with batched mutations and a curried API that puts the target object as the last argument. No freezing.
- Small. It's just 10 functions.
- Functional API with curried functions
- JavaScript in, JavaScript out
- Batched mutations
npm install immutable-ops --saveimport compose from 'ramda/src/compose';
import ops from 'immutable-ops';
// These are all the available functions.
const {
// Functions operating on objects.
merge,
mergeDeep,
omit,
setIn,
// Functions operating on arrays.
insert,
splice,
push,
filter,
// Functions operating on both
set,
// Placeholder for currying.
__,
} = ops;
const arr = [1, 2, 3];
const pushFour = ops.push(4);
const pushFive = ops.push(5);
// All functions are curried. These functions
// still need the final argument, the array to
// operate on.
expect(pushFive).to.be.a('function');
const pushFourAndFive = compose(pushFive, pushFour);
const result = pushFourAndFive(arr);
// Two new arrays were created during `pushFourAndFive` execution.
expect(result).to.deep.equal([1, 2, 3, 4, 5]);
// Only one new array is created.
const sameResult = ops.batched(batchedOps => {
// batchedOps is able to keep track of mutated
// objects.
return compose(
batchedOps.push(5),
batchedOps.push(4)
)(arr);
});
expect(sameResult).to.deep.equal([1, 2, 3, 4, 5]);A batch token is supplied by the user at the start of a batch, or created by immutable-ops. Each newly created object within a batch is tagged with that token. If a batch using token X operates on an object that is tagged with token X, it is free to mutate it. You can think of it as an ownership; the batch owns the newly created object and therefore is free to mutate it. New batches use a token Y that will never be equal to the previous token.
Tags are not removed; They are assigned to a non-enumerable property @@_______immutableOpsOwnerID which should avoid any collisions.
This token strategy is similar to what ImmutableJS uses to track batches.
Manually using batch tokens
ops.batch gives you access to all the immutable-ops functions that take a token as their additional first argument. Otherwise they are identical to the functions found in ops directly.
import ops from 'immutable-ops';
const token = ops.getBatchToken();
// This object has no batch token, since it was not created by immutable-ops.
const obj = {a: 1, b: 2};
// obj2 is a newly created object tagged with the token.
const obj2 = ops.batch.set(token, 'a', 10, obj);
expect(obj).to.not.equal(obj2)
// Because we operate on obj2 that has the same token as
// we passed to the function, obj2 is mutated.
const obj3 = ops.batch.set(token, 'b', 20, obj2);
expect(obj2).to.equal(obj3);Handling batch tokens implicitly
import ops from 'immutable-ops';
const obj = {a: 1, b: 2};
const obj3 = ops.batched(batchedOps => {
// batchedOps has functions that are bound to a new batch token.
const obj2 = batchedOps.set('a', 10, obj);
return batchedOps.set('b', 20, obj2);
});All operations are curried by default. Functions are curried with ramda.curry. In addition to normal currying behaviour, you can use the ramda placeholder variable available in ops.__ to specify parameters you want to pass arguments for later. Example:
const removeNFromHead = ops.splice(/* startIndex */ 0, /* deleteCount */ops.__, /* valsToAdd */[]);
const removeTwoFromHead = removeNFromHead(2);
const arr = [1, 2, 3];
console.log(removeTwoFromHead(arr));
// [3];Performs a shallow merge on targetObj. mergeObj can be a single object to merge, or a list of objects. If a list is passed as mergeObj, objects to the right in the list will have priority when determining final attributes.
Returns the merged object, which will be a different object if an actual change was detected during the merge.
const result = ops.merge(
// mergeObj
{
a: 'theA',
b: {
c: 'nestedC',
},
},
// targetObj
{
a: 'theA2',
b: {
d: 'nestedD',
},
c: 'theC',
}
);
console.log(result);
// {
// {
// a: 'theA',
// b: {
// c: 'nestedC'
// },
// c: 'theC',
// },
// }Same as merge, but performs merge recursively on attributes that are objects (not arrays).
const result = ops.deepMerge(
// mergeObj
{
a: 'theA',
b: {
c: 'nestedC',
},
},
// targetObj
{
a: 'theA2',
b: {
d: 'nestedD',
},
c: 'theC',
}
);
console.log(result);
// {
// {
// a: 'theA',
// b: {
// c: 'nestedC',
// d: 'nestedD',
// },
// c: 'theC',
// },
// }Returns an object, with the value at path set to value. path can be a dot-separated list of attribute values or an array of attribute names to traverse.
const obj = {
location: {
city: 'San Francisco',
},
};
const newObj = ops.setIn(['location', 'city'], 'Helsinki', obj);
console.log(newObj);
// {
// location: {
// city: 'Helsinki',
// },
// };Returns a shallow copy of targetObj without the keys specified in keysToOmit. keysToOmit can be a single key name or an array of key names.
const obj = {
a: true,
b: true,
};
const result = ops.omit('a', obj);
console.log(result);
// {
// b: true,
// }Returns a new array with values inserted at starting at index startIndex to targetArray.
const arr = [1, 2, 4];
const result = ops.insert(2, [3], arr);
console.log(result);
// [1, 2, 3, 4]Returns a shallow copy of targetArray with value added to the end. value can be a single value or an array of values to push.
const arr = [1, 2, 3];
const result = ops.push(4, arr);
console.log(result);
// [1, 2, 3, 4]Returns a shallow copy of targetArray with items that func returns true for, when calling it with the item.
const arr = [1, 2, 3, 4];
const result = ops.filter(item => item % 2 === 0, arr);
console.log(result);
// [2, 4]Like Array.prototype.splice, but operates on a shallow copy of targetArray and returns the shallow copy.
const arr = [1, 2, 3, 3, 3, 4];
const result = ops.splice(2, 2, [], arr);
console.log(result);
// [1, 2, 3, 4]Returns a shallow copy of target with its value at index or key key set to value.
const arr = [1, 2, 5];
const result = ops.set(2, 3, arr);
console.log(result);
// [1, 2, 3]
const obj = {
a: 'X',
b: 'theB',
};
const resultObj = ops.set('a', 'theA', obj);
console.log(resultObj);
// {
// a: 'theA',
// b: 'theB',
// }-
BREAKING: No
getImmutableOpsfunction, which was the main export, is exported anymore because options were removed. Now the object containing the operation functions is exported directly. -
BREAKING: removed option to choose whether operations are curried. Functions are now always curried.
-
BREAKING: former batched mutations API totally replaced.
-
BREAKING: batched mutations implementation changed.
Previously newly created objects were tagged with a "can mutate" tag, and references to those objects were kept in a list. After the batch was finished, the list was processed by removing the tags from each object in the list.
Now a batch token is created at the start of a batch (or supplied by the user). Each newly created object is tagged with that token. If a batch using token
Xoperates on an object that is tagged with tokenX, it is free to mutate it. New batches use a tokenYthat will never be equal to the previous token.Tags are not removed anymore; They are assigned to a non-enumerable property
@@_______immutableOpsOwnerIDwhich should avoid any collisions.This token strategy is similar to what ImmutableJS uses to track batches.
MIT. See LICENSE.