Function getStringSlices

app/utilities/search.ts:23–102

(
  stringValue: string,
  matchingIndices: ReadonlyArray<{ start: number; end: number }>,
  windowSize: number
)

//
// If stringValue length is less than the windowSize, then we should return all the string slices of the string
export function getStringSlices(
  stringValue: string,
  matchingIndices: ReadonlyArray<{ start: number; end: number }>,
  windowSize: number
): Array<StringSlice> {
  const slices: StringSlice[] = [];

  const addSlice = (isMatch: boolean, slice: string) => {
    if (slice.length > 0) {
      slices.push({ isMatch, slice });
    }
  };

  const addEllipsis = () => {
    addSlice(false, "…");
  };

  const calculateWindow = (): { start: number; end: number } => {
    if (stringValue.length <= windowSize) {
      return { start: 0, end: stringValue.length };
    }

    const largestMatch = matchingIndices.reduce(
      (largestMatch, match) => {
        if (match.end - match.start > largestMatch.end - largestMatch.start) {
          return match;
        }

        return largestMatch;
      },
      { start: 0, end: 0 }
    );

    const largestMatchLength = largestMatch.end - largestMatch.start;

    const start =
      largestMatch.start - Math.floor(windowSize / 2 - largestMatchLength / 2);
    const end =
      largestMatch.end + Math.floor(windowSize / 2 - largestMatchLength / 2);

    return {
      start: Math.max(start, 0),
      end: Math.min(end, stringValue.length),
    };
  };

  const window = calculateWindow();

  let currentIndex = window.start;

  if (window.start > 0) {
    addEllipsis();
  }

  for (const { start, end } of matchingIndices) {
    if (start < window.start && end < window.start) {
      continue;
    } else if (start > window.end) {