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    Immutable version of dot-prop with some extensions.

    npm install dot-prop-immutable

    The motivation for this module is to have a simple utility for changing state in a React-Redux application without mutating the existing state of plain JavaScript objects. If you are going for real immutable data collections take a look at the cool library Immutable.js. A good practice is not to mix the immutable data collections with mutable objects because it can lead to confusion. Immutable objects are not accessed by the default semantics, but implemented by setters and getters.

    This library implements 3 helper functions:

    get(object, path) --> value
    set(object, path, value) --> object
    delete(object, path) --> object

    None of the functions mutate the input object. For efficiency, the returned object is not a deep clone of the original, but a shallow copy of the objects in the mutated path.


    const dotProp = require('dot-prop-immutable');
    let state = { todos: [] }, index = 0;
    // Add todo:
    state = dotProp.set(state, 'todos', list => [...list, {text: 'cleanup', complete: false}])
    // or with destructuring assignment
    state = {...state, todos: [...state.todos, {text: 'cleanup', complete: false}]};
    //=>  { todos: [{text: 'cleanup', complete: false}] }
    // Complete todo:
    state = dotProp.set(state, `todos.${index}.complete`, true)
    // or with destructuring assignment
    state = {...state, todos: [
    	...state.todos.slice(0, index),
    	{...state.todos[index], complete: true},
    	...state.todos.slice(index + 1)
    //=>  { todos: [{text: 'cleanup', complete: true}] }
    // Delete todo:
    state = dotProp.delete(state, `todos.${index}`)
    // or with destructuring assignment
    state = {...state, todos: [
    	...state.todos.slice(0, index),
    	...state.todos.slice(index + 1)
    //=>  { todos: [] }


    Access a nested property by a dot path

    // Getter
    dotProp.get({foo: {bar: 'unicorn'}}, '')
    //=> 'unicorn'
    dotProp.get({foo: {bar: 'a'}}, 'foo.notDefined.deep')
    //=> undefined
    dotProp.get({foo: {bar: 'a'}}, 'foo.notDefined.deep', 'default value')
    //=> default value
    dotProp.get({foo: {'': 'unicorn'}}, '\\.dot')
    //=> 'unicorn'

    or use a property array as a path.

    // Use an array as get path
    dotProp.get({foo: {'': 'unicorn'}}, ['foo', ''])
    //=> 'unicorn'

    It is also possible to index into an array where the special index $end refers to the last element of the array.

    const obj = {foo: [{ bar: 'gold-unicorn'}, 'white-unicorn', 'silver-unicorn']};
    // Index into array
    dotProp.get(obj, 'foo.1')
    //=> 'white-unicorn'
    dotProp.get(obj, '')
    //=> 'gold-unicorn'
    // Index into array with $end
    dotProp.get(obj, 'foo.$end')
    //=> 'silver-unicorn'
    // If obj is an array
    dotProp.get([{ bar: 'gold-unicorn'}, 'white-unicorn', 'silver-unicorn'], '')
    //=> 'gold-unicorn'


    Modify a nested property by a dot path

    // Setter
    const obj = {foo: {bar: 'a'}};
    const obj1 = dotProp.set(obj, '', 'b');
    //obj1 => {foo: {bar: 'b'}}
    const obj2 = dotProp.set(obj1 , 'foo.baz', 'x');
    //obj2 => {foo: {bar: 'b', baz: 'x'}}

    where obj, obj1, obj2, obj3 all are different objects.

    Use a function to modify the selected property, where first argument is the old value.

    // Setter where value is a function (get and set current value)
    dotProp.set({foo: {bar: 'a'}}, '', v => v + 'bc')
    //=> {foo: {bar: 'abc'}}

    Modify a nested array

    const obj = {foo: [{ bar: 'gold-unicorn'}, 'white-unicorn', 'silver-unicorn']};
    // Index into array
    dotProp.set(obj, 'foo.1', 'platin-unicorn')
    //=> {foo: [{bar: 'gold-unicorn'}, 'platin-unicorn', 'silver-unicorn']}
    dotProp.set(obj, '', 'platin-unicorn')
    //=> {foo: [{bar: 'platin-unicorn'}, 'white-unicorn', 'silver-unicorn']}
    // Index into array with $end
    dotProp.set(obj, 'foo.$end', 'platin-unicorn')
    //=> {foo: [{ bar: 'gold-unicorn'}, 'white-unicorn', 'platin-unicorn']}


    Delete a nested property/array by a dot path

    const obj = {foo: [{ bar: 'gold-unicorn'}, 'white-unicorn', 'silver-unicorn']};
    // delete
    dotProp.delete(obj, 'foo.$end');
    //=> {foo: [{ bar: 'gold-unicorn'}, 'white-unicorn']}
    dotProp.delete(obj, '');
    //=> {foo: [{}, 'white-unicorn', 'silver-unicorn']}


    Toggle a boolean a value by a dot path.

    const obj = {foo: { bar: true } };
    // toggle
    dotProp.toggle(obj, '');
    //=> {foo: { bar: false } }


    Merge a value by a dot path.

    The target value must be an object, array, null, or undefined.

    • If target is an object, Object.assign({}, target, param) is used.
    • If target an array, target.concat(param) is used.
    • If target is null or undefined, the value is simply set.
    const obj = {foo: { bar: {a:1, b:2 } };
    // merge object
    dotProp.merge(obj, '', {c:3} );
    //=> {foo: { bar:{ a:1, b:2, c:3} } }
    var arr = {foo: { bar: [1, 2] } };
    // merge array
    dotProp.merge(arr, '', [3, 4] );
    //=> {foo: { bar:[1, 2, 3, 4 ] }




    npm i dot-prop-immutable

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    • jonathanmh
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