errors: consistent format for error message

Consistently use printf-style strings for error messages that
do not need a custom argument order or processing of arguments.

PR-URL: https://github.com/nodejs/node/pull/16904
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 39 insertions, 0 deletions

diff --git a/tools/eslint-rules/prefer-util-format-errors.js b/tools/eslint-rules/prefer-util-format-errors.js
new file mode 100644
index 0000000000..c3f4819e43
--- /dev/null
+++ b/tools/eslint-rules/prefer-util-format-errors.js
@@ -0,0 +1,39 @@
+'use strict';
+
+const errMsg = 'Please use a printf-like formatted string that util.format' +
+               ' can consume.';
+
+function isArrowFunctionWithTemplateLiteral(node) {
+  return node.type === 'ArrowFunctionExpression' &&
+         node.body.type === 'TemplateLiteral';
+}
+
+function isDefiningError(node) {
+  return node.expression &&
+         node.expression.type === 'CallExpression' &&
+         node.expression.callee &&
+         node.expression.callee.name === 'E';
+}
+
+module.exports = {
+  create: function(context) {
+    return {
+      ExpressionStatement: function(node) {
+        if (!isDefiningError(node))
+          return;
+
+        const msg = node.expression.arguments[1];
+        if (!isArrowFunctionWithTemplateLiteral(msg))
+          return;
+
+        const { expressions } = msg.body;
+        const hasSequentialParams = msg.params.every((param, index) => {
+          const expr = expressions[index];
+          return expr && expr.type === 'Identifier' && param.name === expr.name;
+        });
+        if (hasSequentialParams)
+          context.report(msg, errMsg);
+      }
+    };
+  }
+};