Added space-before-function-paren rule #1897

cameron-mcateer · 2016-12-18T06:15:32Z

PR checklist

Addresses an existing issue: #0000
New feature, bugfix, or enhancement
- Includes tests
Documentation update

What changes did you make?

I added a rule which lets you enforce whether a space should exist or not before the opening parenthesis of a named function, anonymous function, async arrow function, method, or constructor. This is meant to be similar to the same-named rule for eslint.

Is there anything you'd like reviewers to focus on?

Performance of rule evaluation (specifically the use of a ts.Scanner for checking spaces before parenthesis).
The completeness of the tests

palantirtech · 2016-12-18T06:15:32Z

Thanks for your interest in palantir/tslint, @cameron-mcateer! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

nchen63 · 2016-12-19T03:45:27Z

can you turn on circleCI?

cameron-mcateer · 2016-12-19T04:13:05Z

~~Sorry I am new to contributing to tslint and can't find anything anything enabling circleCI. Do you have a link?~~
@nchen63 circleCI complete

adidahiya · 2016-12-19T16:29:47Z

src/rules/spaceBeforeFunctionParenRule.ts

+import * as Lint from "../index";
+
+const ALWAYS_OR_NEVER = {
+  enum: ["always", "never"],


please use 4-space indentation in TS files like the rest of the project

adidahiya · 2016-12-19T16:30:29Z

src/rules/spaceBeforeFunctionParenRule.ts

+    super.visitMethodSignature(node);
+  }
+
+  private _visitFunction(node: ts.Node): void {


we don't use the underscore naming convention -- the private modifier is enough to denote encapsulation.

adidahiya · 2016-12-19T16:31:40Z

src/rules/spaceBeforeFunctionParenRule.ts

+      failure = this.createFailure(openParen.getStart(), 1, Rule.MISSING_WHITESPACE_ERROR, fix);
+    }
+
+    if (failure) {


please avoid implicit type coercion to boolean -- do an explicit undefined check instead

adidahiya · 2016-12-19T16:32:01Z

src/rules/spaceBeforeFunctionParenRule.ts

+  private _visitFunction(node: ts.Node): void {
+    const options = this.getOptions();
+
+    if (options === null || options.length === 0 || Object.keys(options).length === 0) {


this check looks overly defensive; I don't think any of your code will break if you remove this. it's better to be consistent with other rules in code style.

adidahiya · 2016-12-19T16:33:31Z

src/rules/spaceBeforeFunctionParenRule.ts

+  private getOption(option: string): string {
+    const allOptions = this.getOptions();
+    if (allOptions == null || allOptions.length === 0) {
+        return null;


please avoid using null explicitly; return undefined instead

adidahiya · 2016-12-19T16:33:55Z

src/rules/spaceBeforeFunctionParenRule.ts

+      }
+    });
+
+    if (!openParen || (isArrow && !isAsyncArrow)) {


no implicit boolean coercion

adidahiya · 2016-12-19T16:34:47Z

src/rules/spaceBeforeFunctionParenRule.ts

+    type: "style",
+    typescriptOnly: false,
+  };
+  public static INVALID_WHITESPACE_ERROR = "Should be no space before paren";


suggestion: "Spaces before function parens are disallowed"

adidahiya · 2016-12-19T16:35:32Z

src/rules/spaceBeforeFunctionParenRule.ts

+    typescriptOnly: false,
+  };
+  public static INVALID_WHITESPACE_ERROR = "Should be no space before paren";
+  public static MISSING_WHITESPACE_ERROR = "Should be a space before paren";


suggestion: "Missing whitespace before function parens"

cameron-mcateer · 2016-12-19T16:58:25Z

@adidahiya Thanks for the feedback! Changes made.

cameron-mcateer · 2016-12-19T20:54:57Z

Updated. Renamed file from test.js.int to test.js.lint.

nchen63 · 2016-12-20T00:41:12Z

src/rules/spaceBeforeFunctionParenRule.ts

+
+            * \`"anonymous"\` checks before the opening paren in anonymous functions
+            * \`"named"\` checks before the opening paren in named functions
+            * \`"asyncArrow"\` checks before the opening paren in async arrow functions,


don't need comma at the end here

nchen63 · 2016-12-20T00:57:27Z

src/rules/spaceBeforeFunctionParenRule.ts

+        super.visitMethodSignature(node);
+    }
+
+    private visitFunction(node: ts.Node): void {


can you break this up into smaller functions?

nchen63 · 2016-12-20T01:08:25Z

src/rules/spaceBeforeFunctionParenRule.ts

+export class Rule extends Lint.Rules.AbstractRule {
+    public static metadata: Lint.IRuleMetadata = {
+        description: "Require or disallow a space before function parenthesis",
+        optionExamples: [`[true, {"anonymous": "always", "named": "never", "asyncArrow": "always"}]`],


seems tedious to need to specify a value for each type of function. How about allowing something like [true, "always"] or even [true], which defaults to the same thing.

@nchen63

deferring to @nchen63 for final review

cameron-mcateer · 2016-12-20T08:49:37Z

@nchen63 Split visitFunction() into multiple functions and moved location of failure to the space character for "never" failures.

nchen63 · 2016-12-23T17:13:17Z

src/rules/spaceBeforeFunctionParenRule.ts

+            * \`"named"\` checks before the opening paren in named functions
+            * \`"asyncArrow"\` checks before the opening paren in async arrow functions
+            * \`"method"\` checks before the opening paren in class methods
+            *v\`"constructor"\` checks before the opening paren in class constructors


nchen63 · 2016-12-23T17:19:05Z

src/rules/spaceBeforeFunctionParenRule.ts

+    }
+
+    private getOption(optionName: string): string {
+        const allOptions = this.getOptions();


can you parse the options once in the constructor so that doing this check will be a quick lookup?

cameron-mcateer · 2016-12-23T18:39:37Z

@nchen63 Woops sorry that snuck in. Also caching the options now.

cameron-mcateer · 2016-12-23T19:03:53Z

Rebased on latest to keep tests passing.

nchen63 · 2016-12-23T20:54:32Z

src/rules/spaceBeforeFunctionParenRule.ts

+
+class FunctionWalker extends Lint.RuleWalker {
+    private scanner: ts.Scanner;
+    private cachedOptions: any;


here's how you can avoid using any for cachedOptions:

interface CachedOptions { anonymous?: boolean; asyncArrow?: boolean; } type optionType = "anonymous" | "asyncArrow"; let cachedOptions: CachedOptions = {}; // cache the options let optionArray: optionType[] = ["anonymous", "asyncArrow"] for (const option of optionArray) { cachedOptions[option] = true; }

Oh thank you. I kept using the string values in so that it allows the user to ignore certain rules (as opposed to forcing a failure if they are not consistent).

nchen63 · 2016-12-24T01:05:39Z

@cameron-mcateer thanks!

For future reference, it would be helpful if you didn't squash and force push your changes so I can see the diff between updates.

cameron-mcateer · 2016-12-24T01:25:23Z

@nchen63 Thanks! Will do. I'm used to amending all my PR commits. I'll keep that in mind from now on.

cameron-mcateer force-pushed the master branch from e98e041 to 444ff58 Compare December 18, 2016 06:53

adidahiya previously requested changes Dec 19, 2016

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adidahiya assigned nchen63 Dec 19, 2016

cameron-mcateer force-pushed the master branch from 444ff58 to 936078a Compare December 19, 2016 16:55

cameron-mcateer force-pushed the master branch from 936078a to dec8fed Compare December 19, 2016 20:51

nchen63 suggested changes Dec 20, 2016

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cameron-mcateer force-pushed the master branch 3 times, most recently from 6395bc7 to 665ab24 Compare December 20, 2016 08:45

nchen63 suggested changes Dec 23, 2016

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cameron-mcateer force-pushed the master branch from 665ab24 to 4ce2f1d Compare December 23, 2016 18:38

cameron-mcateer force-pushed the master branch from 4ce2f1d to 5d6cf1c Compare December 23, 2016 19:00

nchen63 reviewed Dec 23, 2016

View reviewed changes

Added space-before-function-paren rule

b562822

cameron-mcateer force-pushed the master branch from 5d6cf1c to b562822 Compare December 23, 2016 21:40

nchen63 approved these changes Dec 24, 2016

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nchen63 merged commit 60e55d6 into palantir:master Dec 24, 2016

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Added space-before-function-paren rule #1897

Added space-before-function-paren rule #1897

cameron-mcateer commented Dec 18, 2016 •

edited

palantirtech commented Dec 18, 2016

nchen63 commented Dec 19, 2016

cameron-mcateer commented Dec 19, 2016 •

edited

adidahiya Dec 19, 2016

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cameron-mcateer commented Dec 20, 2016

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cameron-mcateer commented Dec 23, 2016

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nchen63 commented Dec 24, 2016

cameron-mcateer commented Dec 24, 2016

Added space-before-function-paren rule #1897

Added space-before-function-paren rule #1897

Conversation

cameron-mcateer commented Dec 18, 2016 • edited

PR checklist

What changes did you make?

Is there anything you'd like reviewers to focus on?

palantirtech commented Dec 18, 2016

nchen63 commented Dec 19, 2016

cameron-mcateer commented Dec 19, 2016 • edited

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cameron-mcateer commented Dec 19, 2016

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nchen63 commented Dec 24, 2016

cameron-mcateer commented Dec 24, 2016

cameron-mcateer commented Dec 18, 2016 •

edited

cameron-mcateer commented Dec 19, 2016 •

edited