tupl

Reusable key generator especially for ES6's Map objects

Installation

    npm i tupl --save

Usage

    const tupl = require('tupl');
    var key = tupl(...args);

Example

    const tupl = require('tupl');
    var map = new Map();
    map.set(tupl('some', 'key', 1.2345, true, this), {name: 'Test'});
    console.log(map.get(tupl('some', 'key', 1.2345, true, this)).name);
    // Output: Test

tupl API

• tupl(...args) Returns input dependent unique key for passed arguments

      var key1 = tupl(1, 2, 3);
      var key2 = tupl(1, 2, 3);
      var key3 = tupl(1, 2, 3, 4);
        
      assert(key1 === key2);
      assert(key1 !== key3);

• tupl.create(ns) Creates a namespace bounded tupl generator.

  • @param ns: This parameter accepts all kind of types (such as number, string, symbol, object or array instances, ...etc). When ns is undefined then it returns global tupl generator.

      const CUSTOM_NAMESPACE = Symbol('SomeCustomValue');
      var myTupl = tupl.create(CUSTOM_NAMESPACE);
        
      assert(tupl('a') !== myTupl('a'));

  Since I've added destroy() feature to Key API, it may cause some unwanted issues between modules which used tupl on runtime. So, if you decided to use tupl on your own npm module, I highly recommend using a namespace bounded tupl generator.

• tupl.keys(ns) Returns an iterator whic iterates used keys in given namespace When ns is undefined then it returns keys of global tupl generator.

      const CUSTOM_NAMESPACE = Symbol('SomeCustomValue');
      var myTupl = tupl.create(CUSTOM_NAMESPACE);
        
      var key1 = tupl(1);
      var key2 = tupl(1, 'a');
        
      var myKey1 = myTupl(1, 'a', 'b'); 
        
      var keys = [...tupl.keys()];
      var myKeys = [...tupl.keys(CUSTOM_NAMESPACE)];
        
      assert(keys.length === 2);
      assert(keys[0] === key1);
      assert(keys[1] === key2);
        
      assert(myKeys.length === 1);
      assert(myKeys[0] === myKey1);

Key API

    const tupl = require('tupl');
    let key = tupl('a', 'b', 'c', 'd');

• Event 'destroy' (new in 1.2) Emitted when key is destroyed

  var key = tupl(1, 2, 3);
  key.root.on('destroy', function (eventTarget) {
      assert(eventTarget.raw === 1);
      done();
  });
  key.destroy();

• Event 'ref' (new in 1.2) Emitted when key is generated

  var key = tupl(1, 2, 3);
  key.parent.on('ref', function (eventTarget) {
      assert(eventTarget.raw === 2);
      done();
      eventTarget.destroy();
      key.destroy();
  });
  tupl(1, 2);

• Event 'descendant' (new in 1.2) Emitted when sub key is generated

  var key = tupl(1, 2);
  key.root.on('descendant', function (newRef, eventTarget) {
      assert(newRef.raw === 5);
      assert(eventTarget.raw === 1);
      done();
      key.destroy();
      newRef.destroy();
  });
    
  tupl(1, 2, 3, 4, 5);

• Event 'ancestor' (new in 1.2) Emitted when one of ancestors is generated

  var key = tupl(1, 2, 3, 4, 5);
  key.on('ancestor', function (newRef, eventTarget) {
      assert(newRef.raw === 3);
      assert(eventTarget.raw === 5);
      done();
      eventTarget.destroy();
      newRef.destroy();
  });
  
  tupl(1, 2, 3);

• key.root (new in 1.2) Returns the root key

• key.events (new in 1.2) Returns attached EventEmitter instance

• key.on(name, callback) (new in 1.2) Adds an event listener

• key.once(name, callback) (new in 1.2) Adds an event listener for one time call

• key.off(name = undefined, callback = undefined) (new in 1.2)

  • if @name and @callback parameters are defined then removes specific listener

  • if only @name is defined then removes all @name listeners

  • if none of both parameters are undefined then removes all attached event listeners

• key.ancestors() (new in 1.2) Returns an iterator which iterates the ancestors (parent, parent.parent, ...)

• key.descendants() (new in 1.2) Returns an iterator which iterates the descendants (children(), children().children(), ...)

• key.parent Returns the parent key.

• key.raw Refers to given argument

  console.log(key.raw) Output: d console.log(key.parent.raw) Output: c

• key.destroy() Destroys the current key and its unreferenced ancestors.

  • Unreferenced ancestor example

      let parent = key.parent;
      key.destroy();
      assert(key.destroyed);
      assert(parent.destroyed);

  • Referenced ancestor example

      let parent = key.parent;
      let key2 = tupl('a', 'b', 'c');
      key.destroy();
      assert(parent === key2);
      assert(key.destroyed);
      assert(!parent.destroyed);

• key.destroyed returns true if current key is destroyed

• key.children() returns an iterator which iterates the referenced child keys

      let parent = tupl('a');
      let used = tupl('a', 'b', 'c', 'd');
      let otherUsed = tupl('a', 'b', 'c', 'd', 'e', 'f');
      let children = [...parent.children()];
  
      assert(children.length === 2);
      assert(children[0] === used);
      assert(children[1] === otherUsed);

• key.hasRef returns true if key is generated directly;

      let used = tupl('a', 'b', 'c', 'd');
      let parentParent = tupl('a', 'b');
        
      assert(used.hasRef);
      assert(!used.parent.hasRef);
      assert(used.parent.parent === parentParent);
      assert(used.parent.parent.hasRef);

Notes

Please see tests for other examples

Change Log

• 1.1.0 New API features
• 1.0.0 Initial release