lib/compiler.js
function hasOutDatedTemplateCache (mainCompilation) {
  const childCompiler = getChildCompiler(mainCompilation.compiler);
  /**
   * @type {WeakMap<HtmlWebpackChildCompiler, boolean>|undefined}
   */
  let hasOutdatedChildCompilerDependenciesMap = hasOutdatedCompilationDependenciesMap.get(mainCompilation);
  // Create map for childCompiler if none exist
  if (!hasOutdatedChildCompilerDependenciesMap) {
    hasOutdatedChildCompilerDependenciesMap = new WeakMap();
    hasOutdatedCompilationDependenciesMap.set(mainCompilation, hasOutdatedChildCompilerDependenciesMap);
  }
  // Try to get the `checkChildCompilerCache` result from cache
  let isOutdated = hasOutdatedChildCompilerDependenciesMap.get(childCompiler);
  if (isOutdated !== undefined) {
    return isOutdated;
  }
  // If `checkChildCompilerCache` has never been called for the given
  // `mainCompilation` and `childCompiler` combination call it:
  isOutdated = isChildCompilerCacheOutdated(mainCompilation, childCompiler);
  hasOutdatedChildCompilerDependenciesMap.set(childCompiler, isOutdated);
  return isOutdated;
}
function hasOutDatedTemplateCache (mainCompilation) {
  const childCompiler = getChildCompiler(mainCompilation.compiler);
  /**
   * @type {WeakMap<HtmlWebpackChildCompiler, boolean>|undefined}
   */
  let hasOutdatedChildCompilerDependenciesMap = hasOutdatedCompilationDependenciesMap.get(mainCompilation);
  // Create map for childCompiler if none exist
  if (!hasOutdatedChildCompilerDependenciesMap) {
    hasOutdatedChildCompilerDependenciesMap = new WeakMap();
    hasOutdatedCompilationDependenciesMap.set(mainCompilation, hasOutdatedChildCompilerDependenciesMap);
  }
  // Try to get the `checkChildCompilerCache` result from cache
  let isOutdated = hasOutdatedChildCompilerDependenciesMap.get(childCompiler);
  if (isOutdated !== undefined) {
    return isOutdated;
  }
  // If `checkChildCompilerCache` has never been called for the given
  // `mainCompilation` and `childCompiler` combination call it:
  isOutdated = isChildCompilerCacheOutdated(mainCompilation, childCompiler);
  hasOutdatedChildCompilerDependenciesMap.set(childCompiler, isOutdated);
  return isOutdated;
}
function hasOutDatedTemplateCache ( mainCompilation ) { const childCompiler = getChildCompiler ( mainCompilation . compiler ) ; /**
   * @type {WeakMap<HtmlWebpackChildCompiler, boolean>|undefined}
   */ let hasOutdatedChildCompilerDependenciesMap = hasOutdatedCompilationDependenciesMap . get ( mainCompilation ) ; // Create map for childCompiler if none exist if ( ! hasOutdatedChildCompilerDependenciesMap ) { hasOutdatedChildCompilerDependenciesMap = new WeakMap ( ) ; hasOutdatedCompilationDependenciesMap . set ( mainCompilation , hasOutdatedChildCompilerDependenciesMap ) ; } // Try to get the `checkChildCompilerCache` result from cache let isOutdated = hasOutdatedChildCompilerDependenciesMap . get ( childCompiler ) ; if ( isOutdated !== undefined ) { return isOutdated ; } // If `checkChildCompilerCache` has never been called for the given // `mainCompilation` and `childCompiler` combination call it: isOutdated = isChildCompilerCacheOutdated ( mainCompilation , childCompiler ) ; hasOutdatedChildCompilerDependenciesMap . set ( childCompiler , isOutdated ) ; return isOutdated ; }
Returns `true` if the file dependencies of the current childCompiler
for the given mainCompilation are outdated.

Uses the `hasOutdatedCompilationDependenciesMap` cache if possible.

@param {WebpackCompilation} mainCompilation
@returns {boolean}
Returns true if the file dependencies of the current childCompiler for the given mainCompilation are outdated .