Method _getLineNumber

external/.scrollLibs.js:15377–15385

(target = this)

    return this._getLineNumberRelativeTo()
  }
  _getLineNumber(target = this) {
    if (this._cachedLineNumber) return this._cachedLineNumber
    let lineNumber = 1
    for (let particle of this.root.getTopDownArrayIterator()) {
      if (particle === target) return lineNumber
      lineNumber++
    }
    return lineNumber
  }
  isBlankLine() {
    return !this.length && !this.getLine()
  }