range-parser

Range header field parser.

Installation

npm install range-parser

API

import { parse, combineRanges } from "range-parser";

parse(size, header)

Parse the given header string where size is the size of the selected representation that is to be partitioned into subranges. A type and an array of subranges will be returned or negative numbers indicating an error parsing.

• -2 signals a malformed header string
• -1 signals an unsatisfiable range

Note: size must be a safe integer or a TypeError is thrown. The maximum supported file size is Number.MAX_SAFE_INTEGER (9,007,199,254,740,991 bytes), about 9 PB.

// parse header from request
var header = req.headers.range;
var subranges = typeof header === "string" ? parse(size, header) : -2;

// the type of the subranges
if (typeof subranges === "object" && subranges.type === "bytes") {
  // the ranges
  subranges.ranges.forEach(function (r) {
    // do something with r.start and r.end
  });
}

combineRanges(ranges)

Overlapping and adjacent ranges will be combined and returned. Returned ranges include the index used to preserve their original order.

const subranges = parse(100, "bytes=50-55,0-10,5-10,56-60");
if (typeof subranges === "object") {
  combineRanges(subranges.ranges);
  // => [
  //      { start: 50, end: 60, index: 0 },
  //      { start: 0,  end: 10, index: 1 }
  //    ]
}

License

MIT