add ANSI coloring option to sys.inspect and, by default, to the repl

1 files changed, 63 insertions, 18 deletions

diff --git a/lib/sys.js b/lib/sys.js
index 8480facb7e..1d34713f3a 100644
--- a/lib/sys.js
+++ b/lib/sys.js
@@ -33,10 +33,51 @@ var error = exports.error = function (x) {
  *
  * @param {Object} value The object to print out
  * @param {Boolean} showHidden Flag that shows hidden (not enumerable)
- * properties of objects.
+ *    properties of objects.
+ * @param {Number} depth Depth in which to descend in object. Default is 2.
+ * @param {Boolean} colors Flag to turn on ANSI escape codes to color the
+ *    output. Default is false (no coloring).
  */
-exports.inspect = function (obj, showHidden, depth) {
+exports.inspect = function (obj, showHidden, depth, colors) {
   var seen = [];
+
+  var stylize = function (str, styleType) {
+    // http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
+    var styles = { 'bold'      : [1,  22]
+                 , 'italic'    : [3,  23]
+                 , 'underline' : [4,  24]
+                 , 'inverse'   : [7,  27]
+                 , 'white'     : [37, 39]
+                 , 'grey'      : [90, 39]
+                 , 'black'     : [30, 39]
+                 , 'blue'      : [34, 39]
+                 , 'cyan'      : [36, 39]
+                 , 'green'     : [32, 39]
+                 , 'magenta'   : [35, 39]
+                 , 'red'       : [31, 39]
+                 , 'yellow'    : [33, 39]
+                 };
+    var style = { "special": "grey"
+                , "number": "blue"
+                , "boolean": "blue"
+                , "undefined": "red"
+                , "null": "red"
+                , "string": "green"
+                , "date": "magenta"
+                //, "name": intentionally not styling
+                , "regexp": "cyan"
+                }[styleType];
+    if (style) {
+      return '\033[' + styles[style][0] + 'm' + str +
+             '\033[' + styles[style][1] + 'm';
+    } else {
+      return str;
+    }
+  };
+  if (! colors) {
+    stylize = function(str, styleType) { return str; };
+  }
+
   function format(value, recurseTimes) {
     // Provide a hook for user-specified inspect functions.
     // Check that value is an object with an inspect function on it
@@ -50,16 +91,18 @@ exports.inspect = function (obj, showHidden, depth) {
 
     // Primitive types cannot have properties
     switch (typeof value) {
-      case 'undefined': return 'undefined';
-      case 'string':    return JSON.stringify(value).replace(/'/g, "\\'")
-                                                    .replace(/\\"/g, '"')
-                                                    .replace(/(^"|"$)/g, "'");
-      case 'number':    return '' + value;
-      case 'boolean':   return '' + value;
+      case 'undefined': return stylize('undefined', 'undefined');
+      case 'string':    return stylize(
+        JSON.stringify(value).replace(/'/g, "\\'")
+                             .replace(/\\"/g, '"')
+                             .replace(/(^"|"$)/g, "'"),
+        'string');
+      case 'number':    return stylize('' + value, 'number');
+      case 'boolean':   return stylize('' + value, 'boolean');
     }
     // For some reason typeof null is "object", so special case here.
     if (value === null) {
-      return 'null';
+      return stylize('null', 'null');
     }
 
     // Look up the keys of the object.
@@ -74,15 +117,15 @@ exports.inspect = function (obj, showHidden, depth) {
     // Functions without properties can be shortcutted.
     if (typeof value === 'function' && keys.length === 0) {
       if (isRegExp(value)) {
-        return '' + value;
+        return stylize('' + value, 'regexp');
       } else {
-        return '[Function]';
+        return stylize('[Function]', 'special');
       }
     }
 
     // Dates without properties can be shortcutted
     if (isDate(value) && keys.length === 0) {
-        return value.toUTCString();
+        return stylize(value.toUTCString(), 'date');
     }
 
     var base, type, braces;
@@ -115,9 +158,9 @@ exports.inspect = function (obj, showHidden, depth) {
 
     if (recurseTimes < 0) {
       if (isRegExp(value)) {
-        return '' + value;
+        return stylize('' + value, "regexp");
       } else {
-        return "[Object]";
+        return stylize("[Object]", "special");
       }
     }
 
@@ -126,13 +169,13 @@ exports.inspect = function (obj, showHidden, depth) {
       if (value.__lookupGetter__) {
         if (value.__lookupGetter__(key)) {
           if (value.__lookupSetter__(key)) {
-            str = "[Getter/Setter]";
+            str = stylize("[Getter/Setter]", "special");
           } else {
-            str = "[Getter]";
+            str = stylize("[Getter]", "special");
           }
         } else {
           if (value.__lookupSetter__(key)) {
-            str = "[Setter]";
+            str = stylize("[Setter]", "special");
           }
         }
       }
@@ -160,7 +203,7 @@ exports.inspect = function (obj, showHidden, depth) {
             }
           }
         } else {
-          str = '[Circular]';
+          str = stylize('[Circular]', 'special');
         }
       }
       if (typeof name === 'undefined') {
@@ -170,11 +213,13 @@ exports.inspect = function (obj, showHidden, depth) {
         name = JSON.stringify('' + key);
         if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
           name = name.substr(1, name.length-2);
+          name = stylize(name, "name");
         }
         else {
           name = name.replace(/'/g, "\\'")
                      .replace(/\\"/g, '"')
                      .replace(/(^"|"$)/g, "'");
+          name = stylize(name, "string");
         }
       }