can-symbol

A symbol polyfill that also includes additional well known symbols used to detail how to operate on different objects.

The following are the additional well-known symbols:

• can.apply(context, args) - How to call this value as a function

• can.getKeyDependencies(key)->? - Returns observable dependencies for the observable key, null if there are none.

• can.getKeyDescriptor(key)->{} - Returns data describing this key's behavior. (PENDING)

• can.getKeyValue(key)->* - Returns the value at key.

• can.getOwnEnumerableKeys()->Array|Iterator - Returns enumerable keys directly on object.

• can.getOwnKeyDescriptor(key)->{} - Returns data describing this key's behavior directly on object.

• can.getOwnKeys()->Array|Iterator - Returns all keys directly on object.

• can.getValue()->* - Returns the internal value of the object.

• can.getValueDependencies()->? - Returns observable dependencies for the observable value, null if there are none.

• can.getValueDescriptor()->{} - Returns data describing this values behavior.

• can.hasOwnKey(key)->Boolean - Returns if the object has key. Like Object.prototype.hasOwnProperty.

• can.isListLike {Boolean} - If something should be list like

• can.isMapLike {Boolean} - If something should be considered map like.

• can.isMoreListLikeThanMapLike {Boolean} - If both a map and a list, this idicates how you should iterate through it.

• can.isValueLike {Boolean} - If this represents a single value (computes, Kefier streams).

• can.new(args...) - Use this value to create a new instance of something.

• can.offEvent(args...) - Stop listening to an event.

• can.offKeyValue(key, callback) - Stop listening to changes in a key.

• can.offValue(callback) - Stop listening to changes in a value.

• can.onEvent(args...) - Listen to an event

• can.onKeyValue(key, callback) - Listen to when a key changes

• can.onKeys(callback) - Listen to when any key changes on this value.

• can.onKeysAdded( callback(keyToValues[, index]) ) - Listen to when keys are added to this value.

• can.onKeysRemoved( callback(keysOrValues[, index]) ) - Listen to when keys are removed from this value.

• can.onValue(callback) - Listen to when the value changes.

• can.getProto() - Get the next object in the proto chain. (PENDING)

• can.setKeyValue(key, value) - Set a key's value.

• can.setValue(value) - Update the value of this value.

• can.keyHasDependencies()-> Boolean

• can.valueHasDependencies() -> Boolean

Use

var canSymbol = require("can-symbol");

// Create a symbol --------------------------
var someSymbol = canSymbol("this is my symbol");


// Set a symbol 'property' ------------------
// Assign it to an object as follows if you need to support
// browsers that don't have native Symbols:
var obj = {};
Object.defineProperty(obj, someSymbol,{
    enumerable: false,
    writable: true,
    configurable: true,
    value: "Hi There!"
});

// ... or use  can-operate
var canReflect = require("can-reflect");
canReflect.set(obj, someSymbol, "Hi There!");

// Read a symbol 'property' ----------------
console.log( obj[someSymbol] ) //-> logs "Hi There!"


// Define behavior for can-operate ----------------
canReflect.set(Set.prototype, canSymbol.for("can.getOwnEnumerableKeys"), function(){
    return this.keys();
});