Preview source code for CLI, useful when display error message with related source.

$ npm install cli-source-preview

'use strict'

const preview = require('cli-source-preview')
const source = `
'use strict'

const chalk = require('chalk')

const PREVIEW_OPTS = {
  offset: 5,
  lineNumber: true,
  delimiter: '\\n'
}
const DELIMITER = '-'.repeat(40)

function rightPad (text, width) {
  return text + (width > text.length ? ' '.repeat(width - text.length) : '')
}
`

// preview line 10
console.log(preview(source, 10))

// preview line 5~8
console.log(preview(source, [5, 8]))

// preview line 12:6
console.log(preview(source, { line: 12, column: 6}))

Get source code parts by line and return with highlighted (CLI) string.

• source (String), source code to preview
• line (Mixed), line number to highlight and preview, types:
  • Array: [ Number, Number ], the line range to preview
  • Object: { line: Number, column: Number }, preivew specified line/column
  • Number: preivew single line
• options (Object), preview options (optional)
  • offset: extra lines number before/after specified line range (default: 5)
  • lineNumber: show line number or not (default: true)
  • delimiter: line delimiter (default: '\n')
  • cliColor: show ASCI CLI highlight color, set false to turn off CLI highlight (default: true)

Return preview parts string of source

Read source code by from/to line range.

• source (String), source code to read
• from (Number), from line
• to (Number), to line
• offset (Number), same as options.offset
• delimiter (String), same as options.delimiter

Return readed source code lines as format:

return [{
  number: Number,
  source: String
}, ...]

MIT