subtitle-parser.ts

import axios from 'axios'
import vttToJson from 'vtt-to-json'
const { default: srtParser2 } = require('srt-parser-2')

import { Subtitle } from '../'
import timeToSeconds from './time-to-seconds'

const subtitleParser = async (subitleUrl: string): Promise<Subtitle[]> => {
  const { data: subtitleData } = await axios.get(subitleUrl)

  const subtitleType = subitleUrl.split('.')[subitleUrl.split('.').length - 1]

  const result: Subtitle[] = []

  if (subtitleType === 'srt') {
    interface srtParserSubtitle {
      startTime: string
      endTime: string
      text: string
    }

    const parser: {
      fromSrt: (data: any) => srtParserSubtitle[]
    } = new srtParser2()

    const parsedSubtitle: srtParserSubtitle[] = parser.fromSrt(subtitleData)

    parsedSubtitle.forEach(({ startTime, endTime, text }) => {
      result.push({
        start: timeToSeconds(startTime.split(',')[0]),
        end: timeToSeconds(endTime.split(',')[0]),
        part: text,
      })
    })
  }

  if (subtitleType === 'vtt') {
    interface vttToJsonSubtitle {
      start: number
      end: number
      part: string
    }

    const parsedSubtitle: vttToJsonSubtitle[] = await vttToJson(subtitleData)

    parsedSubtitle.forEach(({ start, end, part }) => {
      // For some reason this library adds the index of the subtitle at the end of the part, so we cut it
      result.push({
        start: start / 1000,
        end: end / 1000,
        part: part.slice(
          0,
          part.length - part.split(' ')[part.split(' ').length - 1].length,
        ),
      })
    })
  }

  return result
}

export default subtitleParser