Merge pull request #168 from charlespwd/master

Throw slightly better error message when a context variable is not provided
formatjs · Aug 8, 2017 · 33f175c · 33f175c
2 parents 31e87c6 + 63c46fd
commit 33f175c
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Showing 2 changed files with 19 additions and 2 deletions.
diff --git a/src/core.js b/src/core.js
@@ -41,7 +41,18 @@ function MessageFormat(message, locales, formats) {
     // the other `Intl` APIs.
     var messageFormat = this;
     this.format = function (values) {
+      try {
         return messageFormat._format(pattern, values);
+      } catch (e) {
+        if (e.variableId) {
+          throw new Error(
+            'The intl string context variable \'' + e.variableId + '\'' +
+            ' was not provided to the string \'' + message + '\''
+          );
+        } else {
+          throw e;
+        }
+      }
     };
 }
 
@@ -176,7 +187,7 @@ MessageFormat.prototype._findPluralRuleFunction = function (locale) {
 
 MessageFormat.prototype._format = function (pattern, values) {
     var result = '',
-        i, len, part, id, value;
+        i, len, part, id, value, err;
 
     for (i = 0, len = pattern.length; i < len; i += 1) {
         part = pattern[i];
@@ -191,7 +202,9 @@ MessageFormat.prototype._format = function (pattern, values) {
 
         // Enforce that all required values are provided by the caller.
         if (!(values && hop.call(values, id))) {
-            throw new Error('A value must be provided for: ' + id);
+          err = new Error('A value must be provided for: ' + id);
+          err.variableId = id;
+          throw err;
         }
 
         value = values[id];

diff --git a/tests/index.js b/tests/index.js
@@ -317,6 +317,7 @@ describe('IntlMessageFormat', function () {
             it('should fail when the argument in the pattern is not provided', function () {
                 expect(msg.format).to.throwException(function (e) {
                     expect(e).to.be.an(Error);
+                    expect(e.message).to.match(/The intl string context variable 'STATE' was not provided to the string '{STATE}'/);
                 });
             });
 
@@ -327,6 +328,7 @@ describe('IntlMessageFormat', function () {
 
                 expect(formatWithValueNameTypo).to.throwException(function (e) {
                     expect(e).to.be.an(Error);
+                    expect(e.message).to.match(/The intl string context variable 'STATE' was not provided to the string '{STATE}'/);
                 });
             });
 
@@ -346,6 +348,7 @@ describe('IntlMessageFormat', function () {
 
                 expect(formatWithMissingValue).to.throwException(function (e) {
                     expect(e).to.be.an(Error);
+                    expect(e.message).to.match(/The intl string context variable 'ST1ATE' was not provided to the string '{ST1ATE}'/);
                 });
             });
 
@@ -356,6 +359,7 @@ describe('IntlMessageFormat', function () {
 
                 expect(formatWithMissingValue).to.throwException(function (e) {
                     expect(e).to.be.an(Error);
+                    expect(e.message).to.match(/The intl string context variable 'ST1ATE' was not provided to the string '{ST1ATE}'/);
                 });
             });