Obj

let empty: unit => Js.t({..});

empty() returns the empty object {}.

let assign: (Js.t({..}), Js.t({..})) => Js.t({..});

assign(target, source) copies properties from source to target. Properties in target will be overwritten by properties in source if they have the same key. Returns target.

RE
/* Copy an object */

let obj = [%obj {a: 1}];

let copy = Js.Obj.assign(Js.Obj.empty(), obj);

/* prints "{ a: 1 }" */
Js.log(copy);

/* Merge objects with same properties */

let target = [%obj {a: 1, b: 1}];
let source = [%obj {b: 2}];

let obj = Js.Obj.assign(target, source);

/* prints "{ a: 1, b: 2 }" */
Js.log(obj);

/* prints "{ a: 1, b: 2 }", target is modified */
Js.log(target);

let keys: Js.t('a) => array(string);

keys(obj) returns an array of the keys of obj's own enumerable properties.