Convert array of objects to object

array-objects-to-object.md

I have array of objects like that

var arr = [
  { id: 4, name: 'John'},
  { id: 7, name: 'Mary'}
];

I want to convert it to object like that

{
  4: 'John',
  7: 'Mary'
}

There are 4 ways to achieve that

• using .reduce: I like the way because .reduce is used and it is short frequently

_.reduce(arr, function(memo, value) { memo[value.id] = value.name; return memo;}, {});

• using .map and .object: just reference, I don't remember how to use .object almost

_.chain(arr)
  .map(function(value) { return [value.id, value.name];})
  .object()
  .value();

• using .pluck and .object: just reference, I don't remember how to use .object almost

_.object(_.pluck(arr, 'id'), _.pluck(arr, 'name'));

• using .indexBy and .mapObject: just reference. It is long

_.chain(arr)
  .indexOf('id')
  .mapObject(function(value) { return value.name;})
  .value();

convert-form-selector-to-json-object.md

Remember, the function requires jQuery

_.mixin({
    fromFormSelector: fromFormSelector
});

/////////////////////

/**
 * convert form selector to JSON object
 * @param selector
 * @returns {*}
 */
function fromFormSelector(selector) {
    return _.reduceToObject($(selector).serializeArray(), 'name', 'value');
}

Usage

var data = _.fromFormSelector("#login-form"); // return {username: 'abc', password: ''}

reduce-to-object.md

I extends underscore the function to use future.

_.mixin({
    reductToObject: reductToObject
});

/////////////////////

/**
 * convert list of objects to object {item[key] : item[value]}
 * eg: [{id: 4, name: 'John'}, {id:7, name: 'Mary'}] ==> {4: 'John', 7: 'Mary'}
 * @param list
 * @param key
 * @param value
 * @returns {Object}
 */
function reduceToObject(list, key, value) {
    return _.reduce(list, function (memo, item) {
        memo[item[key]] = item[value];
        return memo;
    }, {});
}