Node.js stream.Readable.from() Method
The stream.Readable.from() method is an inbuilt application programming interface of the Stream module which is used to construct Readable Streams out of iterators.
Syntax:
stream.Readable.from( iterable, options )
Parameters: This method accept two parameters as mentioned above and described below:
- iterable: It is an object which implements the Symbol.asyncIterator or Symbol.iterator iterable protocol.
- options: It is an options provided to the new stream.Readable([options]). By default, the Readable.from() method will set options.objectMode to true, unless its not set to false manually.
Return Value: It returns stream.Readable.
Below examples illustrate the use of stream.Readable.from() method in Node.js:
Example 1:
// Node.js program to demonstrate the // stream.Readable.from() method // Constructing readable from stream const { Readable } = require('stream'); // Using async function async function * generate() { yield 'GfG'; yield 'CS-Portal...'; } // Using stream.Readable.from() method const readable = Readable.from(generate()); // Handling data event readable.on('data', (chunk) => { console.log(chunk); }); console.log("Program completed!!"); |
Output:
Program completed!! GfG CS-Portal...
Example 2:
// Node.js program to demonstrate the // stream.Readable.from() // method // Constructing readable from stream const { Readable } = require('stream'); // Using async function async function * generate() { yield 'Nidhi'; yield 'w3wiki'; } // Using stream.Readable.from() method const readable = Readable.from(generate()); // Handling data event readable.on('data', (chunk) => { console.log(chunk.length); }); console.log("Program completed!!"); |
Output:
Program completed!! 5 13
Reference: https://nodejs.org/api/stream.html#stream_stream_readable_from_iterable_options
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