loadsh 入门.md

Some Lodash API

Array

1. chunk(array, [size=1])

   _.chunk(['a', 'b', 'c', 'd'], 2);
   // → [['a', 'b'], ['c', 'd']]
   _.chunk(['a', 'b', 'c', 'd'], 3);
   // → [['a', 'b', 'c'], ['d']]

2. compact(array)

   移除所有 falsey 的值

3. concat(array, [values])

   var array = [1];
   var other = _.concat(array, 2, [3], [[4]]);
   console.log(other);
   // → [1, 2, 3, [4]]
   console.log(array);
   // → [1]

4. difference(array, [values])

   _.difference([3, 2, 1], [4, 2]);
   // → [3, 1]

5. drop(array, [n=1])

   _.drop([1, 2, 3]);
   // → [2, 3]
   _.drop([1, 2, 3], 2);
   // → [3]
   _.drop([1, 2, 3], 5);
   // → []
   _.drop([1, 2, 3], 0);
   // → [1, 2, 3]

6. dropWhile(array, [predicate=_.identity)

   var users = [
     { 'user': 'barney',  'active': false },
     { 'user': 'fred',    'active': false },
     { 'user': 'pebbles', 'active': true }
   ];
   _.dropWhile(users, function(o) { return !o.active; });
   // → objects for ['pebbles']
   // The `_.matches` iteratee shorthand.
   _.dropWhile(users, { 'user': 'barney', 'active': false });
   // → objects for ['fred', 'pebbles']
   // The `_.matchesProperty` iteratee shorthand.
   _.dropWhile(users, ['active', false]);
   // → objects for ['pebbles']
   // The `_.property` iteratee shorthand.
   _.dropWhile(users, 'active');
   // → objects for ['barney', 'fred', 'pebbles']

7. fill(array, value, [start=0], [end=array.length])

   var array = [1, 2, 3];
   
   _.fill(array, 'a');
   console.log(array);
   // → ['a', 'a', 'a']
   
   _.fill(Array(3), 2);
   // → [2, 2, 2]
   
   _.fill([4, 6, 8, 10], '*', 1, 3);
   // → [4, '*', '*', 10]

8. findIndex(array, [predicate=_.identity)

   var users = [
     { 'user': 'barney',  'active': false },
     { 'user': 'fred',    'active': false },
     { 'user': 'pebbles', 'active': true }
   ];
   _.findIndex(users, function(o) { return o.user == 'barney'; });
   // → 0
   // The `_.matches` iteratee shorthand.
   _.findIndex(users, { 'user': 'fred', 'active': false });
   // → 1
   // The `_.matchesProperty` iteratee shorthand.
   _.findIndex(users, ['active', false]);
   // → 0
   // The `_.property` iteratee shorthand.
   _.findIndex(users, 'active');
   // → 2

9. flatten(array, <[depth=1]>)

   _.flatten([1, [2, [3, [4]], 5]]);
   // → [1, 2, [3, [4]], 5]
   _.flattenDeep([1, [2, [3, [4]], 5]]);
   // → [1, 2, 3, 4, 5]
   var array = [1, [2, [3, [4]], 5]];
   _.flattenDepth(array, 1);
   // → [1, 2, [3, [4]], 5]
   _.flattenDepth(array, 2);
   // → [1, 2, 3, [4], 5]

10. fromPairs(pairs)

    _.fromPairs([['fred', 30], ['barney', 40]]);
    // → { 'fred': 30, 'barney': 40 }

11. ​