encodeMappings

tcmts.core.program.encodeMappings · #5qcf736m · term · runs anywhere

import { B64 } from "#codebase/tcmts/core/program";

export function encodeMappings(lines: number[][][]): string {
  const vlq = (n: number) => {
    let v = n < 0 ? (-n << 1) | 1 : n << 1;
    let out = "";
    do {
      let d = v & 31;
      v >>>= 5;
      if (v) d |= 32;
      out += B64[d];
    } while (v);
    return out;
  };
  const prev = [0, 0, 0, 0];
  return lines
    .map((segs) => {
      prev[0] = 0;
      return segs
        .map((seg) => {
          const out = seg.map((v, k) => vlq(v - prev[k]!)).join("");
          seg.forEach((v, k) => (prev[k] = v));
          return out;
        })
        .join(",");
    })
    .join(";");
}

uses

• tcmts.core.program.B64

used by

• tcmts.core.program.transpileForNode