Method solve

src/lib/compare/histogram.ts:234–289

Solve returns a DiffSolution. Internally it uses solveRange to find all matching regions, * then it uses the standard differ to create diffs on the intra-region area.

()

   * then it uses the standard differ to create diffs on the intra-region area.
   */
  solve(): DiffPair[] {
    const joinLines = (lines: string[], start: number, end: number) => {
      if (start >= end) {
        return "";
      }

      const s = lines.slice(start, end).join("\n");
      return s + "\n";
    };
    const lineLen = (line: string) => (line === "" ? 0 : Math.max(1, line.length - 1));

    let apos = 0;
    let bpos = 0;
    let prevRegion = new MatchRegion(0, 0, 0, 0, 0);
    // Find common lines.
    const regions = this.fineSolveRegion(this.solveRange(0, this.aa.length, 0, this.bb.length));
    const pairs: DiffPair[] = [];

    // Calculate block differences.
    for (let i = 0; i <= regions.length; i++) {
      const region = regions[i];
      const aEnd = region ? region.aStart : this.aa.length;
      const bEnd = region ? region.bStart : this.bb.length;
      const aaStr = joinLines(this.aa, prevRegion.aEnd, aEnd);
      const bbStr = joinLines(this.bb, prevRegion.bEnd, bEnd);
      const aDiff = newDiff(apos, lineLen(aaStr), "del");
      const bDiff = newDiff(bpos, lineLen(bbStr), "ins");

      if (aDiff.length > 0 || bDiff.length > 0) {
        pairs.push({
          left: aDiff.length > 0 ? aDiff : undefined,
          right: bDiff.length > 0 ? bDiff : undefined,
        });
      }

      // Perform inline comparison after removing leading and trailing whitespace.
      if (aaStr.length > 0 && bbStr.length > 0) {
        const { left, right } = classify(myersDiff(aaStr, bbStr, { maxEditLength: 100 }));
        left.forEach((d) => (d.offset += aDiff.offset));
        right.forEach((d) => (d.offset += bDiff.offset));
        aDiff.inlineDiffs = left;
        bDiff.inlineDiffs = right;
      }

      if (region) {
        // Equal parts. Because trim is performed, the length of the equal parts needs to be calculated separately.
        const aaComm = joinLines(this.aa, region.aStart, region.aEnd);
        const bbComm = joinLines(this.bb, region.bStart, region.bEnd);
        apos += aaStr.length + aaComm.length;
        bpos += bbStr.length + bbComm.length;
        prevRegion = region;
      }
    }

    return pairs;
  }
}