createLineTable() — tailwindcss Function Reference

Source Code

packages/tailwindcss/src/source-maps/line-table.ts lines 50–100

export function createLineTable(source: string): LineTable {
  let table: number[] = [0]

  // Compute the offsets for the start of each line
  for (let i = 0; i < source.length; i++) {
    if (source.charCodeAt(i) === LINE_BREAK) {
      table.push(i + 1)
    }
  }

  function find(offset: number) {
    // Based on esbuild's binary search for line numbers
    let line = 0
    let count = table.length
    while (count > 0) {
      // `| 0` improves performance (in V8 at least)
      let mid = (count | 0) >> 1
      let i = line + mid
      if (table[i] <= offset) {
        line = i + 1
        count = count - mid - 1
      } else {
        count = mid
      }
    }

    line -= 1

    let column = offset - table[line]

    return {
      line: line + 1,
      column: column,
    }
  }

  function findOffset({ line, column }: Position) {
    line -= 1
    line = Math.min(Math.max(line, 0), table.length - 1)

    let offsetA = table[line]
    let offsetB = table[line + 1] ?? offsetA

    return Math.min(Math.max(offsetA + column, 0), offsetB)
  }

  return {
    find,
    findOffset,
  }
}