@atlaskit/editor-plugin-track-changes/dist/es2019/pm-plugins/filterSteps.js

ShowDiff plugin for @atlaskit/editor-core

import { MAX_STEPS_FROM_BASELINE } from './maxSteps';

/**
 * Returns the filtered steps to ensure we don't track an entire document worth of changes
 */
export function filterSteps(steps, allocations) {
  if (allocations.size <= MAX_STEPS_FROM_BASELINE) {
    return {
      steps,
      allocations
    };
  }

  // Create a new allocation, retaining only the most recent values
  const elements = Array.from(allocations);
  const newAllocation = new Set(elements.slice(-MAX_STEPS_FROM_BASELINE));
  const finalSteps = [];
  let cutoffFound = false;
  for (const step of steps) {
    if (newAllocation.has(step.allocation)) {
      cutoffFound = true;
    }
    // Accept everything after this point otherwise we could have mis-ordered steps
    if (cutoffFound) {
      finalSteps.push(step);
    }
  }
  return {
    steps: finalSteps,
    allocations: newAllocation
  };
}