@rpidanny/pdf2md/lib/models/HeadlineFinder.js

A PDF to Markdown Converter

const { normalizedCharCodeArray } = require('../util/string-functions')

module.exports = class HeadlineFinder {
  constructor (options) {
    this.headlineCharCodes = normalizedCharCodeArray(options.headline)
    this.stackedLineItems = []
    this.stackedChars = 0
  }

  consume (lineItem) {
    // TODO avoid join
    const normalizedCharCodes = normalizedCharCodeArray(lineItem.text())
    const matchAll = this.matchAll(normalizedCharCodes)
    if (matchAll) {
      this.stackedLineItems.push(lineItem)
      this.stackedChars += normalizedCharCodes.length
      if (this.stackedChars === this.headlineCharCodes.length) {
        return this.stackedLineItems
      }
    } else {
      if (this.stackedChars > 0) {
        this.stackedChars = 0
        this.stackedLineItems = []
        this.consume(lineItem) // test again without stack
      }
    }
    return null
  }

  matchAll (normalizedCharCodes) {
    for (var i = 0; i < normalizedCharCodes.length; i++) {
      const headlineChar = this.headlineCharCodes[this.stackedChars + i]
      const textItemChar = normalizedCharCodes[i]
      if (textItemChar !== headlineChar) {
        return false
      }
    }
    return true
  }
}