depth-first-post-plugin.js

function DepthFirstPostPlugin() {}

module.exports = DepthFirstPostPlugin;

DepthFirstPostPlugin.prototype.apply = function(compiler) {
  compiler.plugin('compilation', function(compilation) {
    compilation.plugin('optimize-chunk-order', function(chunks) {
      var checked = {};
      function walk(chunk) {
        var nextIndex = 0;

        chunk.modules.sort(function(a, b) {
          return compilation.modules.indexOf(a) - compilation.modules.indexOf(a);
        });
        var hasher = require('crypto').createHash('md5');
        chunk.updateHash(hasher);
        var ident = hasher.digest('hex');
        if (checked[ident]) {return;}
        checked[ident] = true;

        chunk.modules.forEach(function(module) {
          module.blocks.forEach(function(block) {
            var index = chunk.chunks.reduce(function(carry, chunk, index) {
              if (carry !== -1) {return carry;}
              return chunk.origins.reduce(function(carry, origin) {
                if (carry !== -1) {return carry;}
                return origin.module === module ? index : -1;
              }, -1);
            }, -1);

            if (index !== -1) {
              var child = chunk.chunks[index];
              chunk.chunks.splice(index, 1);
              chunk.chunks.splice(nextIndex, 0, child);
              nextIndex++;
            }
          });
        });
      }
      chunks.forEach(walk);

      checked = {};
      var nextIndex = 0;
      compilation.entries.forEach(function(module) {
        module.chunks[0].forEach(function(chunk) {
          var hasher = require('crypto').createHash('md5');
          chunk.updateHash(hasher);
          var ident = hasher.digest('hex');
          if (checked[ident]) {return;}
          checked[ident] = true;

          var index = chunks.indexOf(chunk);
          if (index !== -1) {
            chunks.splice(index, 1);
            chunks.splice(nextIndex, 0, chunk);
            nextIndex++;
          }
        });
      });
    });
    compilation.plugin('optimize-module-order', function(modules) {
      var nextIndex = 0;
      var checked = {};
      function walkDep(dep) {
        if (dep.module) {
          walk(dep.module);
        }
      }
      function walkDepsOwner(owner) {
        owner.dependencies.forEach(walkDep);
      }
      function walk(module) {
        var ident = module.identifier();
        if (checked[ident]) {return;}
        checked[ident] = true;

        walkDepsOwner(module);
        module.variables.forEach(walkDepsOwner);
        module.blocks.forEach(walkDepsOwner);
        var index = modules.indexOf(module);
        if (index !== -1) {
          modules.splice(index, 1);
          modules.splice(nextIndex, 0, module);
          nextIndex++;
        }
      }
      compilation.entries.forEach(walk);
    });
  });
};