flow like the river

BACK_BACK/node_modules/htmlnano/lib/modules/mergeScripts.js

@@ -0,0 +1,63 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = mergeScripts;
+
+/* Merge multiple <script> into one */
+function mergeScripts(tree) {
+  let scriptNodesIndex = {};
+  let scriptSrcIndex = 1;
+  tree.match({
+    tag: 'script'
+  }, node => {
+    const nodeAttrs = node.attrs || {};
+
+    if (nodeAttrs.src) {
+      scriptSrcIndex++;
+      return node;
+    }
+
+    const scriptType = nodeAttrs.type || 'text/javascript';
+
+    if (scriptType !== 'text/javascript' && scriptType !== 'application/javascript') {
+      return node;
+    }
+
+    const scriptKey = JSON.stringify({
+      id: nodeAttrs.id,
+      class: nodeAttrs.class,
+      type: scriptType,
+      defer: nodeAttrs.defer !== undefined,
+      async: nodeAttrs.async !== undefined,
+      index: scriptSrcIndex
+    });
+
+    if (!scriptNodesIndex[scriptKey]) {
+      scriptNodesIndex[scriptKey] = [];
+    }
+
+    scriptNodesIndex[scriptKey].push(node);
+    return node;
+  });
+
+  for (const scriptNodes of Object.values(scriptNodesIndex)) {
+    let lastScriptNode = scriptNodes.pop();
+    scriptNodes.reverse().forEach(scriptNode => {
+      let scriptContent = (scriptNode.content || []).join(' ');
+      scriptContent = scriptContent.trim();
+
+      if (scriptContent.slice(-1) !== ';') {
+        scriptContent += ';';
+      }
+
+      lastScriptNode.content = lastScriptNode.content || [];
+      lastScriptNode.content.unshift(scriptContent);
+      scriptNode.tag = false;
+      scriptNode.content = [];
+    });
+  }
+
+  return tree;
+}