feat(ngError): add error message compression and better error messages

- add toThrowNg matcher

1 files changed, 47 insertions, 0 deletions

diff --git a/src/ngError.js b/src/ngError.js
new file mode 100644
index 00000000..d054336c
--- /dev/null
+++ b/src/ngError.js
@@ -0,0 +1,47 @@
+'use strict';
+
+/**
+ * @description
+ *
+ * This object extends the error class and provides interpolation capability
+ * to make it easier to write and read Error messages within Angular. It can
+ * be called as follows:
+ *
+ * throw ngError(13, 'This {0} is {1}', foo, bar);
+ *
+ * The above will replace {0} with the value of foo, and {1} with the value of
+ * bar. The object is not restricted in the number of arguments it can take.
+ *
+ * If fewer arguments are specified than necessary for interpolation, the extra
+ * interpolation markers will be preserved in the final string.
+ *
+ * @param {...} arguments The first argument to this object is the error
+ *     number, the second argument the message with templated points for
+ *     Interpolation (of the for {0} for the first, {1} for the second and
+ *     so on). The second argument onwards are interpolated into the error
+ *     message string in order.
+ */
+function ngError() {
+  var message = '[NgErr' + arguments[0] + '] ' + arguments[1],
+      i = 0,
+      l = arguments.length - 2,
+      curlyRegexp, arg;
+
+  for (; i < l; i++) {
+    curlyRegexp = new RegExp("\\{" + i + "\\}", "gm");
+    arg = arguments[i + 2];
+
+    if (isFunction(arg)) {
+      arg = arg.toString().replace(/ \{[\s\S]*$/, '');
+    } else if (!isString(arg)) {
+      arg = toJson(arg);
+    }
+
+    message = message.replace(curlyRegexp, arg);
+  }
+
+  // even if we are called as constructor we can bypass the new ngError instance and return
+  // an instance of a real Error that contains correct stack info + extra frame for ngError call
+  // TODO(i): can we rewrite the stack string to remove ngError frame?
+  return new Error(message);
+}