# pseudomap

A thing that is a lot like ES6 `Map`, but without iterators, for use in environments where `for..of` syntax and `Map` are not available.

If you need iterators, or just in general a more faithful polyfill to ES6 Maps, check out [es6-map](http://npm.im/es6-map).

If you are in an environment where `Map` is supported, then that will be returned instead, unless `process.env.TEST_PSEUDOMAP` is set.

You can use any value as keys, and any value as data. Setting again with the identical key will overwrite the previous value.

Internally, data is stored on an `Object.create(null)` style object. The key is coerced to a string to generate the key on the internal data-bag object. The original key used is stored along with the data.

In the event of a stringified-key collision, a new key is generated by appending an increasing number to the stringified-key until finding either the intended key or an empty spot.

Note that because object traversal order of plain objects is not guaranteed to be identical to insertion order, the insertion order guarantee of `Map.prototype.forEach` is not guaranteed in this implementation. However, in all versions of Node.js and V8 where this module works, `forEach` does traverse data in insertion order.

## API

Most of the [Map API](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map), with the following exceptions:

1. A `Map` object is not an iterator.
2. `values`, `keys`, and `entries` methods are not implemented, because they return iterators.
3. The argument to the constructor can be an Array of `[key, value]` pairs, or a `Map` or `PseudoMap` object. But, since iterators aren't used, passing any plain-old iterator won't initialize the map properly.

## USAGE

Use just like a regular ES6 Map.

```javascript
var PseudoMap = require('pseudomap')

// optionally provide a pseudomap, or an array of [key,value] pairs
// as the argument to initialize the map with
var myMap = new PseudoMap()

myMap.set(1, 'number 1')
myMap.set('1', 'string 1')
var akey = {}
var bkey = {}
myMap.set(akey, { some: 'data' })
myMap.set(bkey, { some: 'other data' })
```


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