anything.js

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anything.js

var undef;
var Readable = require('stream').Readable;
var classic = require('classic');

¶

AnythingStreams are readable streams that can buffer/emit anything(including null and undefined values). This is done by manually modifying the _readableState buffer. This is a hacky but needed because the Readable classes ends when a null values is passed to the 'push' method.

The class provides an implementation for the '_read' method. Subclasses need to implement the '_next' method to yield more data.
```
var AnythingStream = classic({
  constructor: function AnythingStream(options) {
```
¶

Initialize readable state by invoking the superclass constructor.
```
    Readable.call(this, options);
  },

  _read: function() {
```
¶

Save the readable state locally
```
    var state = this._readableState;
```
¶

Get the next value
```
    var next = this._next();
```
¶

If a null or undefined value is emitted, we can't pass it using 'this.push' or the stream would end prematurely, instead we update the internal readable state manually to trick the Readable class into thinking that something meaningful was pushed.
```
    if (next === undef || next === null) {
      state.length += 1;
      state.buffer.push(next);
      state.reading = false;
    } else {
```
¶

Normal values can be passed directly to the Readable class
```
      this.push(next);
    }
```
¶

Since nulls and undefined values are allowed, the '_done' method is implemented in by subclasses to signal that the stream has no more data.
```
    if (this._done()) this.push(null);
  }
}, Readable);


module.exports = AnythingStream;
```