New Rule: max-file-line-count (palantir#1360)

README.md

@@ -276,6 +276,7 @@ Core rules are included in the `tslint` package.
 * `label-position` enforces labels only on sensible statements.
 * `label-undefined` checks that labels are defined before usage.
 * `linebreak-style` checks that line breaks used in source files are either linefeed or carriage-return linefeeds. By default linefeeds are required. This rule accepts one parameter, either "LF" or "CRLF".
+* `max-file-line-count` sets the maximum number of lines for files.
 * `max-line-length` sets the maximum length of a line.
 * `member-access` enforces using explicit visibility on class members
     * `"check-accessor"` enforces explicit visibility on get/set accessors

src/rules/maxFileLineCountRule.ts

@@ -0,0 +1,67 @@
+/**
+ * @license
+ * Copyright 2013 Palantir Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import * as Lint from "../lint";
+import * as ts from "typescript";
+
+export class Rule extends Lint.Rules.AbstractRule {
+    /* tslint:disable:object-literal-sort-keys */
+    public static metadata: Lint.IRuleMetadata = {
+        ruleName: "max-file-line-count",
+        description: "Requires files to remain under a certain number of lines",
+        rationale: Lint.Utils.dedent`
+            Limiting the number of lines allowed in a file allows files to remain small, 
+            single purpose, and maintainable.`,
+        optionsDescription: "An integer indicating the maximum number of lines.",
+        options: {
+            type: "number",
+            minimum: "1",
+        },
+        optionExamples: ["[true, 300]"],
+        type: "maintainability",
+    };
+    /* tslint:enable:object-literal-sort-keys */
+
+    public static FAILURE_STRING_FACTORY = (lineCount: number, lineLimit: number) => {
+        let msg = `This file has ${lineCount} lines, which exceeds the maximum of ${lineLimit} lines allowed. `;
+        msg += `Consider breaking this file up into smaller parts`;
+        return msg;
+    };
+
+    public isEnabled(): boolean {
+        if (super.isEnabled()) {
+            const option = this.getOptions().ruleArguments[0];
+            if (typeof option === "number" && option > 0) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {
+        const ruleFailures: Lint.RuleFailure[] = [];
+        const lineLimit: number = this.getOptions().ruleArguments[0];
+        const lineCount: number = sourceFile.getLineStarts().length;
+        const disabledIntervals = this.getOptions().disabledIntervals;
+
+        if (lineCount > lineLimit && disabledIntervals.length === 0) {
+            const errorString = Rule.FAILURE_STRING_FACTORY(lineCount, lineLimit);
+            ruleFailures.push(new Lint.RuleFailure(sourceFile, 0, 1, errorString, this.getOptions().ruleName));
+        }
+
+        return ruleFailures;
+    }
+}

src/tsconfig.json

@@ -83,6 +83,7 @@
         "rules/labelPositionRule.ts",
         "rules/labelUndefinedRule.ts",
         "rules/linebreakStyleRule.ts",
+        "rules/maxFileLineCountRule.ts",
         "rules/maxLineLengthRule.ts",
         "rules/memberAccessRule.ts",
         "rules/memberOrderingRule.ts",

test/rules/max-file-line-count/default/test.ts.lint

@@ -0,0 +1,23 @@
+namespace App {
+~ [This file has 23 lines, which exceeds the maximum of 10 lines allowed. Consider breaking this file up into smaller parts]
+    class GiveMeANumber {
+
+        /* tslint:disable:no-any */
+        private num:any = 10;
+        /* tslint:enable:no-any */
+
+        //This is some kind of comment
+        constructor(){
+            this.giveNumber();
+        }
+
+        /*
+        Here is another comment
+        It's very helpful.
+        */
+
+        public giveNumber = () =>{  
+            alert(this.num);
+        };
+    }
+}

test/rules/max-file-line-count/default/tslint.json

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "max-file-line-count": [true, 10]
+  }
+}

test/rules/max-file-line-count/disabled/test.ts.lint

@@ -0,0 +1,23 @@
+/* tslint:disable:max-file-line-count */
+//This file NEEDS to be very long, so we've disabled this rule here
+
+namespace App {
+    class GiveMeANumber {
+
+        //THis is a comment about something
+        private num = 10;
+
+        constructor(){
+            this.giveNumber();
+        }
+
+        /*
+        Here is another comment
+        It's very helpful.
+        */
+
+        public giveNumber = () =>{  
+            alert(this.num);
+        };
+    }
+}

test/rules/max-file-line-count/disabled/tslint.json

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "max-file-line-count": [true, 10]
+  }
+}

test/tsconfig.json

@@ -79,6 +79,7 @@
         "../src/rules/labelPositionRule.ts",
         "../src/rules/labelUndefinedRule.ts",
         "../src/rules/linebreakStyleRule.ts",
+        "../src/rules/maxFileLineCountRule.ts",
         "../src/rules/maxLineLengthRule.ts",
         "../src/rules/memberAccessRule.ts",
         "../src/rules/memberOrderingRule.ts",