From a1b100d304e271736251986c405238d3f29faa1b Mon Sep 17 00:00:00 2001
From: Cory Thompson <cthompson@tamhsc.edu>
Date: Thu, 3 Oct 2019 23:02:15 -0500
Subject: [PATCH] added only-arrow-functions converter and unit tests

---
 src/rules/converters.ts                       |  2 +
 src/rules/converters/only-arrow-functions.ts  | 25 +++++++
 .../tests/only-arrow-functions.test.ts        | 71 +++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 src/rules/converters/only-arrow-functions.ts
 create mode 100644 src/rules/converters/tests/only-arrow-functions.test.ts

diff --git a/src/rules/converters.ts b/src/rules/converters.ts
index 782e17f47..f1509a708 100644
--- a/src/rules/converters.ts
+++ b/src/rules/converters.ts
@@ -82,6 +82,7 @@ import { convertNoVarRequires } from "./converters/no-var-requires";
 import { convertObjectLiteralKeyQuotes } from "./converters/object-literal-key-quotes";
 import { convertObjectLiteralShorthand } from "./converters/object-literal-shorthand";
 import { convertOneVariablePerDeclaration } from "./converters/one-variable-per-declaration";
+import { convertOnlyArrowFunctions } from "./converters/only-arrow-functions";
 import { convertPreferConst } from "./converters/prefer-const";
 import { convertPreferForOf } from "./converters/prefer-for-of";
 import { convertPreferFunctionOverMethod } from "./converters/prefer-function-over-method";
@@ -193,6 +194,7 @@ export const converters = new Map([
     ["object-literal-key-quotes", convertObjectLiteralKeyQuotes],
     ["object-literal-shorthand", convertObjectLiteralShorthand],
     ["one-variable-per-declaration", convertOneVariablePerDeclaration],
+    ["only-arrow-functions", convertOnlyArrowFunctions],
     ["prefer-const", convertPreferConst],
     ["prefer-function-over-method", convertPreferFunctionOverMethod],
     ["prefer-readonly", convertPreferReadonly],
diff --git a/src/rules/converters/only-arrow-functions.ts b/src/rules/converters/only-arrow-functions.ts
new file mode 100644
index 000000000..17fa60abf
--- /dev/null
+++ b/src/rules/converters/only-arrow-functions.ts
@@ -0,0 +1,25 @@
+import { RuleConverter } from "../converter";
+
+export const convertOnlyArrowFunctions: RuleConverter = tslintRule => {
+    const notices: string[] = [];
+
+    if (tslintRule.ruleArguments.includes("allow-declarations")) {
+        notices.push("ESLint does not support allowing standalone function declarations.");
+    }
+
+    if (tslintRule.ruleArguments.includes("allow-named-functions")) {
+        notices.push(
+            "ESLint does not support allowing named functions defined with the function keyword.",
+        );
+    }
+
+    return {
+        rules: [
+            {
+                ...(notices.length > 0 && { notices }),
+                ruleName: "prefer-arrow/prefer-arrow-functions",
+            },
+        ],
+        plugins: ["prefer-arrow"],
+    };
+};
diff --git a/src/rules/converters/tests/only-arrow-functions.test.ts b/src/rules/converters/tests/only-arrow-functions.test.ts
new file mode 100644
index 000000000..decbb63c3
--- /dev/null
+++ b/src/rules/converters/tests/only-arrow-functions.test.ts
@@ -0,0 +1,71 @@
+import { convertOnlyArrowFunctions } from "../only-arrow-functions";
+
+describe(convertOnlyArrowFunctions, () => {
+    test("conversion without arguments", () => {
+        const result = convertOnlyArrowFunctions({
+            ruleArguments: [],
+        });
+
+        expect(result).toEqual({
+            rules: [
+                {
+                    ruleName: "prefer-arrow/prefer-arrow-functions",
+                },
+            ],
+            plugins: ["prefer-arrow"],
+        });
+    });
+
+    test("conversion with allow-declarations argument", () => {
+        const result = convertOnlyArrowFunctions({
+            ruleArguments: ["allow-declarations"],
+        });
+
+        expect(result).toEqual({
+            rules: [
+                {
+                    notices: ["ESLint does not support allowing standalone function declarations."],
+                    ruleName: "prefer-arrow/prefer-arrow-functions",
+                },
+            ],
+            plugins: ["prefer-arrow"],
+        });
+    });
+
+    test("conversion with allow-named-functions argument", () => {
+        const result = convertOnlyArrowFunctions({
+            ruleArguments: ["allow-named-functions"],
+        });
+
+        expect(result).toEqual({
+            rules: [
+                {
+                    notices: [
+                        "ESLint does not support allowing named functions defined with the function keyword.",
+                    ],
+                    ruleName: "prefer-arrow/prefer-arrow-functions",
+                },
+            ],
+            plugins: ["prefer-arrow"],
+        });
+    });
+
+    test("conversion with all arguments", () => {
+        const result = convertOnlyArrowFunctions({
+            ruleArguments: ["allow-declarations", "allow-named-functions"],
+        });
+
+        expect(result).toEqual({
+            rules: [
+                {
+                    notices: [
+                        "ESLint does not support allowing standalone function declarations.",
+                        "ESLint does not support allowing named functions defined with the function keyword.",
+                    ],
+                    ruleName: "prefer-arrow/prefer-arrow-functions",
+                },
+            ],
+            plugins: ["prefer-arrow"],
+        });
+    });
+});