--- /dev/null
+array-index
+===========
+### Invoke getter/setter functions on array-like objects
+[](http://travis-ci.org/TooTallNate/array-index)
+
+
+This little module provides an `ArrayIndex` constructor function that you can
+inherit from with your own objects. When a numbered property gets read, then the
+`ArrayIndex.get` function on the object will be invoked. When a numbered property gets
+set, then the `ArrayIndex.set` function on the object will be invoked.
+
+
+Installation
+------------
+
+Install with `npm`:
+
+``` bash
+$ npm install array-index
+```
+
+
+Examples
+--------
+
+A quick silly example, using `Math.sqrt()` for the "getter":
+
+``` js
+var ArrayIndex = require('array-index');
+
+// let's just create a singleton instance.
+var a = new ArrayIndex();
+
+// the "ArrayIndex.get" function is invoked for each "a[n]" access.
+// it is given a single argument, the "index" currently being accessed.
+// so here, we're passing in the `Math.sqrt()` function, so accessing
+// "a[9]" will return `Math.sqrt(9)`.
+a[ArrayIndex.get] = Math.sqrt;
+
+// the "ArrayIndex.get" and "ArrayIndex.set" functions are only invoked up
+// to "a.length", so we must set that manually.
+a.length = 10;
+
+console.log(a);
+// [ 0,
+// 1,
+// 1.4142135623730951,
+// 1.7320508075688772,
+// 2,
+// 2.23606797749979,
+// 2.449489742783178,
+// 2.6457513110645907,
+// 2.8284271247461903,
+// 3 ]
+```
+
+Here's an example of creating a subclass of `ArrayIndex` using `util.inherits()`:
+
+``` js
+var ArrayIndex = require('array-index');
+var inherits = require('util').inherits;
+
+function MyArray (length) {
+ // be sure to call the ArrayIndex constructor in your own constructor
+ ArrayIndex.call(this, length);
+
+ // the "set" object will contain values at indexes previously set,
+ // so that they can be returned in the "getter" function. This is just a
+ // silly example, your subclass will have more meaningful logic.
+ Object.defineProperty(this, 'set', {
+ value: Object.create(null),
+ enumerable: false
+ });
+}
+
+// inherit from the ArrayIndex's prototype
+inherits(MyArray, ArrayIndex);
+
+MyArray.prototype[ArrayIndex.get] = function (index) {
+ if (index in this.set) return this.set[index];
+ return index * 2;
+};
+
+MyArray.prototype[ArrayIndex.set] = function (index, v) {
+ this.set[index] = v;
+};
+
+
+// and now you can create some instances
+var a = new MyArray(15);
+a[9] = a[10] = a[14] = '_';
+a[0] = 'nate';
+
+console.log(a);
+// [ 'nate', 2, 4, 6, 8, 10, 12, 14, 16, '_', '_', 22, 24, 26, '_' ]
+```
+
+API
+---
+
+The `ArrayIndex` base class is meant to be subclassed, but it also has a few
+convenient functions built-in.
+
+### "length" → Number
+
+The length of the ArrayIndex instance. The `ArrayIndex.get` and `ArrayIndex.set` functions will
+only be invoked on the object up to this "length". You may set this length at any
+time to adjust the amount range where the getters/setters will be invoked.
+
+### "toArray()" → Array
+
+Returns a new regular Array instance with the same values that this ArrayIndex
+class would have. This function calls the `ArrayIndex.get` function repeatedly from
+`0...length-1` and returns the "flattened" array instance.
+
+### "toJSON()" → Array
+
+All `ArrayIndex` instances get basic support for `JSON.stringify()`, which is
+the same as a "flattened" Array being stringified.
+
+### "toString()" → String
+
+The `toString()` override is basically just `array.toArray().toString()`.
+
+### "format()" → String
+
+The `inspect()` implementation for the REPL attempts to mimic what a regular
+Array looks like in the REPL.
+
+
+License
+-------
+
+(The MIT License)
+
+Copyright (c) 2012 Nathan Rajlich <nathan@tootallnate.net>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Code Review / simantics / district.git / blobdiff