import * as RangeParser from 'range-parser'; declare var console: { assert(b: boolean): void }; console.assert(RangeParser(200, `malformed`) === RangeParser.Result.invaild); console.assert(RangeParser(200, `bytes=500-20`) === RangeParser.Result.unsatisifiable); const range = RangeParser(1000, `bytes=0-499`); if (typeof range !== 'number') { console.assert(range.type === `bytes`); console.assert(range.length === 1); }