From 751ec708a0e2820857d0826041b34190649d8690 Mon Sep 17 00:00:00 2001
From: Sam Killgallon <sam.killgallon@gmail.com>
Date: Mon, 5 Mar 2018 22:19:19 +0000
Subject: [PATCH] Debounce linting to prevent running on every keypress

---
 package.json | 5 +++++
 readme.md    | 6 +++++-
 src/ruby.ts  | 7 ++++++-
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/package.json b/package.json
index a05a080a5..2c59faef5 100644
--- a/package.json
+++ b/package.json
@@ -161,6 +161,11 @@
           "description": "Path to the rct-complete command.  Set this to an absolute path to select from multiple installed Ruby versions.",
           "isExecutable": true
         },
+        "ruby.lintDebounceTime": {
+          "type": "integer",
+          "default": 500,
+          "description": "Time (ms) to wait after keypress before running enabled linters. Ensures linters are only run when typing has finished and not for every keypress"
+        },
         "ruby.lint": {
           "type": "object",
           "description": "Set individual ruby linters to use",
diff --git a/readme.md b/readme.md
index 1cae43032..514ea0049 100644
--- a/readme.md
+++ b/readme.md
@@ -58,7 +58,11 @@ Enable each one in your workspace or user settings:
 	"fasterer": true,
 	"debride": true,
 	"ruby-lint": true
-}
+},
+
+// Time (ms) to wait after keypress before running enabled linters. Ensures
+// linters are only run when typing has finished and not for every keypress
+"ruby.lintDebounceTime": 500,
 
 //advanced: set command line options for some linters:
 "ruby.lint": {
diff --git a/src/ruby.ts b/src/ruby.ts
index d1e5247c4..00db5da4b 100644
--- a/src/ruby.ts
+++ b/src/ruby.ts
@@ -10,6 +10,7 @@ import { RubyDocumentFormattingEditProvider } from './format/rubyFormat';
 import * as utils from './utils';
 import { registerTaskProvider } from './task/rake';
 import { Config as LintConfig } from './lint/lintConfig';
+import * as debounce from 'lodash/debounce';
 
 export function activate(context: ExtensionContext) {
 	const subs = context.subscriptions;
@@ -131,8 +132,12 @@ function registerLinters(ctx: ExtensionContext) {
 		linters.run(e.document);
 	}
 
+	// Debounce linting to prevent running on every keypress, only run when typing has stopped
+	const lintDebounceTime = vscode.workspace.getConfiguration('ruby').lintDebounceTime;
+	const executeDebouncedLinting = debounce(executeLinting, lintDebounceTime);
+
 	ctx.subscriptions.push(vscode.window.onDidChangeActiveTextEditor(executeLinting));
-	ctx.subscriptions.push(vscode.workspace.onDidChangeTextDocument(executeLinting));
+	ctx.subscriptions.push(vscode.workspace.onDidChangeTextDocument(executeDebouncedLinting));
 	ctx.subscriptions.push(vscode.workspace.onDidChangeConfiguration(() => {
 		const docs = vscode.window.visibleTextEditors.map(editor => editor.document);
 		console.log("Config changed. Should lint:", docs.length);