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Range header field parser.


This is a Node.js module available through the npm registry. Installation is done using the npm install command:

$ npm install range-parser


var parseRange = require('range-parser')

parseRange(size, header, options)

Parse the given header string where size is the maximum size of the resource. An array of ranges will be returned or negative numbers indicating an error parsing.

  • -2 signals a malformed header string
  • -1 signals an unsatisfiable range
// parse header from request
var range = parseRange(size, req.headers.range)

// the type of the range
if (range.type === 'bytes') {
  // the ranges
  range.forEach(function (r) {
    // do something with r.start and r.end


These properties are accepted in the options object.


Specifies if overlapping & adjacent ranges should be combined, defaults to false. When true, ranges will be combined and returned as if they were specified that way in the header.

parseRange(100, 'bytes=50-55,0-10,5-10,56-60', { combine: true })
// => [
//      { start: 0,  end: 10 },
//      { start: 50, end: 60 }
//    ]