lib/compiler.js
function isChildCompilerCacheOutdated (mainCompilation, childCompiler) {
  // If the compilation was never run there is no invalid cache
  if (!childCompiler.compilationStartedTimestamp) {
    return false;
  }
  // Check if any dependent file was changed after the last compilation
  const fileTimestamps = mainCompilation.fileTimestamps;
  const isCacheOutOfDate = childCompiler.fileDependencies.some((fileDependency) => {
    const timestamp = fileTimestamps.get(fileDependency);
    // If the timestamp is not known the file is new
    // If the timestamp is larger then the file has changed
    // Otherwise the file is still the same
    return !timestamp || timestamp > childCompiler.compilationStartedTimestamp;
  });
  return isCacheOutOfDate;
}
function isChildCompilerCacheOutdated (mainCompilation, childCompiler) {
  // If the compilation was never run there is no invalid cache
  if (!childCompiler.compilationStartedTimestamp) {
    return false;
  }
  // Check if any dependent file was changed after the last compilation
  const fileTimestamps = mainCompilation.fileTimestamps;
  const isCacheOutOfDate = childCompiler.fileDependencies.some((fileDependency) => {
    const timestamp = fileTimestamps.get(fileDependency);
    // If the timestamp is not known the file is new
    // If the timestamp is larger then the file has changed
    // Otherwise the file is still the same
    return !timestamp || timestamp > childCompiler.compilationStartedTimestamp;
  });
  return isCacheOutOfDate;
}
function isChildCompilerCacheOutdated ( mainCompilation , childCompiler ) { // If the compilation was never run there is no invalid cache if ( ! childCompiler . compilationStartedTimestamp ) { return false ; } // Check if any dependent file was changed after the last compilation const fileTimestamps = mainCompilation . fileTimestamps ; const isCacheOutOfDate = childCompiler . fileDependencies . some ( ( fileDependency ) => { const timestamp = fileTimestamps . get ( fileDependency ) ; // If the timestamp is not known the file is new // If the timestamp is larger then the file has changed // Otherwise the file is still the same return ! timestamp || timestamp > childCompiler . compilationStartedTimestamp ; } ) ; return isCacheOutOfDate ; }
Returns `true` if the file dependencies of the given childCompiler are outdated.

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