Implement tslint enum-naming to enforce PascalCase on enum members (#1474)

1 files changed, 60 insertions, 0 deletions

diff --git a/packages/tslint-config/rules/enumNamingRule.ts b/packages/tslint-config/rules/enumNamingRule.ts
new file mode 100644
index 000000000..56499618f
--- /dev/null
+++ b/packages/tslint-config/rules/enumNamingRule.ts
@@ -0,0 +1,60 @@
+import * as Lint from 'tslint';
+import * as ts from 'typescript';
+
+export class Rule extends Lint.Rules.AbstractRule {
+    public static FAILURE_STRING = `Enum member names should be PascalCase`;
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        return this.applyWithFunction(sourceFile, walk);
+    }
+}
+
+function walk(ctx: Lint.WalkContext<void>): void {
+    // Recursively walk the AST starting with root node, `ctx.sourceFile`.
+    // Call the function `cb` (defined below) for each child.
+    return ts.forEachChild(ctx.sourceFile, cb);
+
+    function cb(node: ts.Node): void {
+        if (node.kind === ts.SyntaxKind.EnumMember) {
+            const keyNode = node.getFirstToken(ctx.sourceFile);
+            if (keyNode !== undefined) {
+                const keyText = keyNode.getText(ctx.sourceFile);
+                if (!isPascalCase(keyText)) {
+                    return ctx.addFailureAtNode(node, Rule.FAILURE_STRING, getFix(keyText, node));
+                }
+            }
+        }
+        // Continue recursion into the AST by calling function `cb` for every child of the current node.
+        return ts.forEachChild(node, cb);
+    }
+
+    function getFix(text: string, node: ts.Node): Lint.Replacement {
+        let fix = toPascalCase(text);
+        // check for `member = value`
+        if (node.getChildCount(ctx.sourceFile) === 3) {
+            const value = node.getLastToken(ctx.sourceFile);
+            if (value !== undefined) {
+                fix += ` = ${value.getText(ctx.sourceFile)}`;
+            }
+        }
+        return new Lint.Replacement(node.getStart(ctx.sourceFile), node.getWidth(ctx.sourceFile), fix);
+    }
+}
+
+// Modified from: https://github.com/jonschlinkert/pascalcase/
+function toPascalCase(str: string): string {
+    let result = str.replace(/([a-z0-9\W])([A-Z])/g, '$1 $2');
+    if (result.length === 1) {
+        return result.toUpperCase();
+    }
+    result = result.replace(/^[\W_\.]+|[\W_\.]+$/g, '').toLowerCase();
+    result = result.charAt(0).toUpperCase() + result.slice(1);
+    return result.replace(/[\W_\.]+(\w|$)/g, (_, ch) => {
+        return ch.toUpperCase();
+    });
+}
+function isPascalCase(s: string): boolean {
+    const regex = /^([A-Z0-9]+[a-z0-9]+)+$/g;
+    const key = s.split('=')[0].trim();
+    return regex.test(key);
+}