debugger: refactor serializing logics by adding PropertyPreview and ObjectPreview

Author: cola119

lib/internal/debugger/inspect_repl.js

@@ -183,6 +183,60 @@ function convertResultToError(result) {
   return err;
 }
 
+class PropertyPreview {
+  constructor(attributes) {
+    ObjectAssign(this, attributes);
+  }
+
+  [customInspectSymbol](depth, opts) {
+    switch (this.type) {
+      case 'string':
+      case 'undefined':
+        return utilInspect(this.value, opts);
+      case 'number':
+      case 'boolean':
+        return opts.stylize(this.value, this.type);
+      case 'object':
+      case 'symbol':
+        if (this.subtype === 'date') {
+          return utilInspect(new Date(this.value), opts);
+        }
+        if (this.subtype === 'array') {
+          return opts.stylize(this.value, 'special');
+        }
+        return opts.stylize(this.value, this.subtype || 'special');
+      default:
+        return this.value;
+    }
+  }
+}
+
+class ObjectPreview {
+  constructor(attributes) {
+    ObjectAssign(this, attributes);
+  }
+
+  [customInspectSymbol](depth, opts) {
+    switch (this.type) {
+      case 'object': {
+        const props = ArrayPrototypeMap(this.properties, (prop, idx) => {
+          const value = utilInspect(new PropertyPreview(prop));
+          if (prop.name === `${idx}`) return value;
+          return `${prop.name}: ${value}`;
+        });
+        if (this.overflow) {
+          ArrayPrototypePush(props, '...');
+        }
+        const singleLine = ArrayPrototypeJoin(props, ', ');
+        const propString = singleLine.length > 60 ? ArrayPrototypeJoin(props, ',\n  ') : singleLine;
+        return this.subtype === 'array' ? `[ ${propString} ]` : `{ ${propString} }`;
+      }
+      default:
+        return this.description;
+    }
+  }
+}
+
 class RemoteObject {
   constructor(attributes) {
     ObjectAssign(this, attributes);
@@ -193,82 +247,34 @@ class RemoteObject {
   }
 
   [customInspectSymbol](depth, opts) {
-    function formatProperty(prop) {
-      switch (prop.type) {
-        case 'string':
-        case 'undefined':
-          return utilInspect(prop.value, opts);
-
-        case 'number':
-        case 'boolean':
-          return opts.stylize(prop.value, prop.type);
-
-        case 'object':
-        case 'symbol':
-          if (prop.subtype === 'date') {
-            return utilInspect(new Date(prop.value), opts);
-          }
-          if (prop.subtype === 'array') {
-            return opts.stylize(prop.value, 'special');
-          }
-          return opts.stylize(prop.value, prop.subtype || 'special');
-
-        default:
-          return prop.value;
-      }
-    }
     switch (this.type) {
       case 'boolean':
       case 'number':
       case 'string':
       case 'undefined':
         return utilInspect(this.value, opts);
-
       case 'symbol':
         return opts.stylize(this.description, 'special');
-
       case 'function': {
         const fnName = extractFunctionName(this.description);
         const formatted = `[${this.className}${fnName}]`;
         return opts.stylize(formatted, 'special');
       }
-
       case 'object':
         switch (this.subtype) {
           case 'date':
             return utilInspect(new Date(this.description), opts);
-
           case 'null':
             return utilInspect(null, opts);
-
           case 'regexp':
             return opts.stylize(this.description, 'regexp');
-
           default:
             break;
         }
         if (this.preview) {
-          const props = ArrayPrototypeMap(
-            this.preview.properties,
-            (prop, idx) => {
-              const value = formatProperty(prop);
-              if (prop.name === `${idx}`) return value;
-              return `${prop.name}: ${value}`;
-            });
-          if (this.preview.overflow) {
-            ArrayPrototypePush(props, '...');
-          }
-          const singleLine = ArrayPrototypeJoin(props, ', ');
-          const propString =
-            singleLine.length > 60 ?
-              ArrayPrototypeJoin(props, ',\n  ') :
-              singleLine;
-
-          return this.subtype === 'array' ?
-            `[ ${propString} ]` : `{ ${propString} }`;
+          return utilInspect(new ObjectPreview(this.preview), opts);
         }
         return this.description;
-
       default:
         return this.description;
     }