gulp-spy

Log the contents of vinyl file streams so you can see what files run through your gulp pipeline.

A log message is written to the console for each file in the stream, and a summary message is optionally written to the console showing the number of files that passed through when the stream is finally flushed.

Install

$ npm install --save-dev gulp-spy

Usage

var gulp = require('gulp'),
    spy = require('gulp-spy');
 
gulp.task('default', function() {
  return gulp.src('*')
    .pipe(spy())
    .pipe(gulp.dest('dist'));
});

API

spy(opts)

opts should be an object with some or all of the following fields, or may be omitted to accept the defaults.

Common options

prefix

Type: string
Default: false

Optionally supply a string which will be displayed at the start of each log message and summary message. When there are multiple gulp tasks running in parallel, this can help clarify which log messages come from which streams. A falsy value means no prefix is used.

    .pipe(spy({
      prefix: 'my prefix:'
    }))

postfix

Type: string
Default: false

Optionally supply a string which will be displayed at the end of each log message and summary message. A falsy value means no postfix is used.

    .pipe(spy({
      postfix: 'with this postfix'
    }))

count

Type: boolean
Default: true

Turn off count mode to stop logging of the summary which shows the number of files that passed through when the stream is finally flushed.

log

Type: boolean
Default: true

Turn off log mode to stop all logging of files and of the summary. This can be useful to enable conditional logging in gulp tasks. With log set to false the gulp-spy pipeline operation becomes a no-op.

Advanced options

console

Type: Console
Default: console

The console to be used for logging. By default, the system console is used, which writes the output to process.stdout. An alternative console can be used to redirect the output to a different output stream.

    .pipe(spy({
      console: new console.Console(getLogOutputStream())
    }))

format

Type: string
Default: 'Processing file %s'

Set a string value to override the format of the log message for each file in the stream. %s will be replaced with the relative path and name of the file. If there is no %s in the string the relative path and name of the file will be appended. A falsy value means the individual files are not logged (but they are still counted, so a summary log message may still be displayed).

    .pipe(spy({
      format: '>' + chalk.yellow('%s')
    }))

timestamp

Type: string
Default: [%H:%M:%S]

Set a string value to override the format of the timestamp shown at the start of each log line. The default format matches the timestamps used by gulp's own log output. Format specifiers supported by strftime can be included. chalk can be used to add color and style if supported by the console. A falsy value means no timestamp is shown.

    .pipe(spy({
      timestamp: 'Hey, it\'s %B %d, %Y %H:%M:%S >'
    }))

    .pipe(spy({
      timestamp: false
    }))

many-format

Type: string
Default: 'Processed %d files'

Set a string value to override the format of the summary message written to the console when more than one file passed through the stream. A falsy value means that no summary message will be written in the case when more than one file passed through the stream. %d will be replaced with the number of files that passed through the stream. If there is no %d in the string the number of files that passed through the stream will be appended. A falsy value means that no summary message will be written in the case when more than one file passed through the stream.

    .pipe(spy({
      'many-format': 'Total: ' + chalk.cyan('%s files')
    }))

one-format

Type: string
Default: 'Processed 1 file'

Set a string value to override the format of the summary message written to the console when exactly one file passed through the stream. A falsy value means that no summary message will be written in the case when exactly one file passed through the stream.

    .pipe(spy({
      'one-format': 'Total: ' + chalk.cyan('1 file')
    }))

zero-format

Type: string
Default: 'No files processed'

Set a string value to override the format of the summary message written to the console when no files passed through the stream. A falsy value means that no summary message will be written in the case when no files passed through the stream.

    .pipe(spy({
      'zero-format': 'No files matched'
    }))

date

Type: Date
Default: false

Supply a date object which will be used for all timestamps. This is really only used for test purposes where repeatable output is desired, as it makes the timestamps themselves rather pointless.

License

MIT © Dave Clark