bes
v3.1.0
Published
Protection from mutation
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Bes
About
Bes is a small library for working with objects without mutation in Javascript. Replacement for the builtin mutating array and object operations are provided, along with a record api for easily creating transformable immutable objects.
Modules
lib/array - 'bes::array'
Replacements for push
pop
shift
unshift
splice
and reverse
that return
arrays and do not mutate the input array.
// bes.array.push
var a = [1, 2, 3];
var a1 = bes.array.push(a, 4);
a1; // [1, 2, 3, 4]
a; // [1, 2, 3];
lib/text - 'bes::object'
Setting and deleting properties on an object. Operations return a copy of the object and do not mutate the original.
var o = {x: 3, y: {z: 4}};
var o1 = bes.object.deleteProperty(
bes.object.setProperty(o, 'w', 3, true),
'x');
o1; // {'y': {'z': 4}, 'w': 3}
o; // {'x': 3, 'y': {'z': 4}});
lib/record - 'bes/record'
Interface for defining an immutable object with transform setters that return copies of the original without mutation.
// Declare record with no prototype and three properties
var R = bes.record.declare(null, ['a', 'b', 'c']);
// crate instance of record
var x = R.create("g", [43], null); // same as new R("g", [43], null)
x instanceof R; // true
x.a; // "g"
x.b; // [43]
x.c; // null
// Using transform setters
var x1 = x.setA("n").setC(100);
x1.a; // "n"
x1.b; // [43]
x1.c; // 100
x.a; // "g"
x.b; // [43]
x.c; // null
Records can subclass and be subclassed by normal objects and extended to create new records:
var S = bes.record.extend(R, ['d']);
var y = S.create(1, 2, 3, 4).setC(100);
y.a; // 1
y.b; // 2
y.c; // 100
y.d; // 4