Class Chunk

deps/v8/tools/system-analyzer/timeline.mjs:257–340

@template T

// ===========================================================================
/** @template T */
class Chunk {
  constructor(index, start, end, items) {
    this.index = index;
    this.start = start;
    this.end = end;
    /** @type {T[]} */
    this.items = items;
    this.height = 0;
  }

  isEmpty() {
    return this.items.length === 0;
  }

  /** @returns {T} */
  last() {
    return this.at(this.size() - 1);
  }

  /** @returns {T} */
  first() {
    return this.at(0);
  }

  /** @returns {T} */
  at(index) {
    return this.items[index];
  }

  size() {
    return this.items.length;
  }

  get length() {
    return this.items.length;
  }

  /** @param {T} event */
  yOffset(event) {
    // items[0]   == oldest event, displayed at the top of the chunk
    // items[n-1] == youngest event, displayed at the bottom of the chunk
    return ((this.indexOf(event) + 0.5) / this.size()) * this.height;
  }

  /** @param {T} event */
  indexOf(event) {
    return this.items.indexOf(event);
  }

  /** @param {T} event */
  has(event) {
    if (this.isEmpty()) return false;
    return this.first().time <= event.time && event.time <= this.last().time;
  }

  /** @param {Chunk<T>[]} chunks */
  next(chunks) {
    return this.findChunk(chunks, 1);