time-to-botec/js/node_modules/@stdlib/streams/node/inspect/lib/main.js
NunoSempere b6addc7f05 feat: add the node modules
Necessary in order to clearly see the squiggle hotwiring.
2022-12-03 12:44:49 +00:00

230 lines
6.1 KiB
JavaScript

/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// MODULES //
var Transform = require( 'readable-stream' ).Transform;
var isFunction = require( '@stdlib/assert/is-function' );
var copy = require( '@stdlib/utils/copy' );
var inherit = require( '@stdlib/utils/inherit' );
var setNonEnumerable = require( '@stdlib/utils/define-nonenumerable-property' );
var setNonEnumerableReadOnly = require( '@stdlib/utils/define-nonenumerable-read-only-property' );
var nextTick = require( '@stdlib/utils/next-tick' );
var DEFAULTS = require( './defaults.json' );
var validate = require( './validate.js' );
var debug = require( './debug.js' );
// FUNCTIONS //
/**
* Implements the `_transform` method.
*
* @private
* @param {(Uint8Array|Buffer|string)} chunk - streamed chunk
* @param {string} encoding - Buffer encoding
* @param {Callback} clbk - callback to invoke after transforming the streamed chunk
*/
function transform( chunk, encoding, clbk ) {
/* eslint-disable no-invalid-this */
this._idx += 1;
debug( 'Received a new chunk. Chunk: %s. Encoding: %s. Index: %d.', chunk.toString(), encoding, this._idx );
this._inspect.call( null, chunk, this._idx );
this.push( chunk );
clbk();
/* eslint-enable no-invalid-this */
}
/**
* Implements the `_flush` method.
*
* @private
* @param {Callback} clbk - callback to invoke after performing flush tasks
*/
function flush( clbk ) {
debug( 'Flushing the stream...' );
clbk();
}
/**
* Gracefully destroys a stream, providing backward compatibility.
*
* @private
* @param {Object} [error] - optional error message
* @returns {InspectStream} stream instance
*/
function destroy( error ) {
/* eslint-disable no-invalid-this */
var self;
if ( this._destroyed ) {
debug( 'Attempted to destroy an already destroyed stream.' );
return this;
}
self = this;
this._destroyed = true;
nextTick( close );
return this;
/**
* Closes a stream.
*
* @private
*/
function close() {
if ( error ) {
debug( 'Stream was destroyed due to an error. Error: %s.', JSON.stringify( error ) );
self.emit( 'error', error );
}
debug( 'Closing the stream...' );
self.emit( 'close' );
}
/* eslint-enable no-invalid-this */
}
// MAIN //
/**
* Inspect stream constructor.
*
* @constructor
* @param {Options} [options] - stream options
* @param {boolean} [options.objectMode=false] - specifies whether the stream should operate in object mode
* @param {NonNegativeNumber} [options.highWaterMark] - specifies the `Buffer` level for when `write()` starts returning `false`
* @param {boolean} [options.allowHalfOpen=false] - specifies whether the stream should remain open even if one side ends
* @param {boolean} [options.readableObjectMode=false] - specifies whether the readable side should be in object mode
* @param {Callback} clbk - callback to invoke upon receiving data
* @throws {TypeError} options argument must be an object
* @throws {TypeError} must provide valid options
* @throws {TypeError} must provide a callback function
* @returns {InspectStream} inspect stream
*
* @example
* function log( chunk, idx ) {
* console.log( 'index: %d', idx );
* console.log( chunk );
* }
*
* var stream = new InspectStream( log );
*
* stream.write( 'a' );
* stream.write( 'b' );
* stream.write( 'c' );
*
* stream.end();
*
* // prints: index: 0
* // prints: a
* // prints: index: 1
* // prints: b
* // prints: index: 2
* // prints: c
*/
function InspectStream( options, clbk ) {
var inspect;
var opts;
var err;
if ( !(this instanceof InspectStream) ) {
if ( arguments.length > 1 ) {
return new InspectStream( options, clbk );
}
return new InspectStream( options );
}
opts = copy( DEFAULTS );
if ( arguments.length > 1 ) {
inspect = clbk;
err = validate( opts, options );
if ( err ) {
throw err;
}
} else {
inspect = options;
}
if ( !isFunction( inspect ) ) {
throw new TypeError( 'invalid argument. Callback argument must be a function. Value: `' + inspect + '`.' );
}
// The stream's writable state should always be in object mode to prevent incoming data from being buffered (concatenated) and thus lose separation...
opts.writableObjectMode = true;
// Make the stream a Transform stream:
debug( 'Creating a transform stream configured with the following options: %s.', JSON.stringify( opts ) );
Transform.call( this, opts );
// The destruction state:
setNonEnumerable( this, '_destroyed', false );
// Initialize a chunk counter:
setNonEnumerable( this, '_idx', -1 );
// Cache a reference to the inspect callback:
setNonEnumerableReadOnly( this, '_inspect', inspect );
return this;
}
/*
* Inherit from the `Transform` prototype.
*/
inherit( InspectStream, Transform );
/**
* Implements the `_transform` method.
*
* @private
* @name _transform
* @memberof InspectStream.prototype
* @type {Function}
* @param {(Buffer|string)} chunk - streamed chunk
* @param {string} encoding - Buffer encoding
* @param {Callback} clbk - callback to invoke after transforming the streamed chunk
*/
setNonEnumerableReadOnly( InspectStream.prototype, '_transform', transform );
/**
* Implements the `_flush` method.
*
* @private
* @name _flush
* @memberof InspectStream.prototype
* @type {Function}
* @param {Callback} clbk - callback to invoke after performing flush tasks
*/
setNonEnumerableReadOnly( InspectStream.prototype, '_flush', flush );
/**
* Gracefully destroys a stream, providing backward compatibility.
*
* @name destroy
* @memberof InspectStream.prototype
* @type {Function}
* @param {Object} [error] - optional error message
* @returns {InspectStream} stream instance
*/
setNonEnumerableReadOnly( InspectStream.prototype, 'destroy', destroy );
// EXPORTS //
module.exports = InspectStream;