程序代写代做代考 Java javascript ### object.builders

### object.builders

> Functions to build objects.

——————————————————————————–

#### frequencies

**Signature:** `_.frequencies(arr:Array)`

Returns an object whose property keys are the values of `arr`’s elements. The
property values are a count of how many times that value appeared in `arr`.

“`javascript
var citations = [“Plato”, “Aristotle”, “Plotinus”, “Plato”];

_.frequencies(citations);
// => { Plato: 2, Aristotle: 1, Plotinus: 1 }
“`

——————————————————————————–

#### merge

**Signature:** `_.merge(obj1:Object[, obj:Object…])`

Merges two or more objects starting with the left-most and applying the keys
rightward.

“`javascript
_.merge({ a: “alpha” }, { b: “beta” });
// => { a: “alpha”, b: “beta” }
“`

——————————————————————————–

#### renameKeys

**Signature:** `_.renameKeys(obj:Object, keyMap:Object)`

Takes an object (`obj`) and a map of keys (`keyMap`) and returns a new object
where the keys of `obj` have been renamed as specified in `keyMap`.

“`javascript
_.renameKeys({ a: 1, b: 2 }, { a: “alpha”, b: “beta” });
// => { alpha: 1, beta: 2 }
“`

——————————————————————————–

#### setPath

**Signature:** `_.setPath(obj:Object, value:Any, ks:Array, defaultValue:Any)`

Sets the value of a property at any depth in `obj` based on the path described
by the `ks` array. If any of the properties in the `ks` path don’t exist, they
will be created with `defaultValue`.

“`javascript
_.setPath({}, “Plotinus”, [“Platonism”, “Neoplatonism”], {});
// => { Platonism: { Neoplatonism: “Plotinus” } }
“`

——————————————————————————–

#### snapshot

**Signature:** `_.snapshot(obj:Object)`

Snapshots/clones an object deeply.

“`javascript
var schools = { plato: “Academy”, aristotle: “Lyceum” };

_.snapshot(schools);
// => { plato: “Academy”, aristotle: “Lyceum” }

schools === _.snapshot(schools);
// => false
“`

——————————————————————————–

**Signature:** `_.updatePath(obj:Object, fun:Function, ks:Array, defaultValue:Any)`

Updates the value at any depth in a nested object based on the path described by
the `ks` array. The function `fun` is called with the current value and is
expected to return a replacement value. If no keys are provided, then the
object itself is presented to `fun`. If a property in the path is missing, then
it will be created with `defaultValue`.

“`javascript
var imperialize = function (val) {
if (val == “Republic) return “Empire”;
else return val;
};

_.updatePath({ rome: “Republic” }, imperialize, [“rome”]);
// => { rome: “Empire” }
“`