Introduce isNonEmptyArray

mjbvz · mjbvz · commit 8392c36a4909 · 2018-11-14T15:51:34.000-08:00
This negation of `isFalsyOrEmpty` works better for type guards. After the check, you know that you have an array with at least one element
diff --git a/src/vs/base/common/arrays.ts b/src/vs/base/common/arrays.ts
@@ -334,7 +334,14 @@ export function move(array: any[], from: number, to: number): void {
  * 	and not empty.
  */
 export function isFalsyOrEmpty(obj: any): boolean {
-	return !Array.isArray(obj) || (<Array<any>>obj).length === 0;
+	return !Array.isArray(obj) || obj.length === 0;
+}
+
+/**
+ * @returns {{true}} if the provided object is an array and has at least one element.
+ */
+export function isNonEmptyArray<T>(obj: ReadonlyArray<T> | undefined | null): obj is Array<T> {
+	return Array.isArray(obj) && obj.length > 0;
 }
 
 /**
diff --git a/src/vs/editor/contrib/codeAction/codeAction.ts b/src/vs/editor/contrib/codeAction/codeAction.ts
@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { flatten, isFalsyOrEmpty, mergeSort } from 'vs/base/common/arrays';
+import { flatten, mergeSort, isNonEmptyArray } from 'vs/base/common/arrays';
 import { CancellationToken } from 'vs/base/common/cancellation';
 import { illegalArgument, isPromiseCanceledError, onUnexpectedExternalError } from 'vs/base/common/errors';
 import { URI } from 'vs/base/common/uri';
@@ -83,15 +83,13 @@ function isValidActionKind(filter: CodeActionFilter | undefined, kind: string |
 }
 
 function codeActionsComparator(a: CodeAction, b: CodeAction): number {
-	const aHasDiags = !isFalsyOrEmpty(a.diagnostics);
-	const bHasDiags = !isFalsyOrEmpty(b.diagnostics);
-	if (aHasDiags) {
-		if (bHasDiags) {
-			return a.diagnostics![0].message.localeCompare(b.diagnostics![0].message);
+	if (isNonEmptyArray(a.diagnostics)) {
+		if (isNonEmptyArray(b.diagnostics)) {
+			return a.diagnostics[0].message.localeCompare(b.diagnostics[0].message);
 		} else {
 			return -1;
 		}
-	} else if (bHasDiags) {
+	} else if (isNonEmptyArray(b.diagnostics)) {
 		return 1;
 	} else {
 		return 0;	// both have no diagnostics
diff --git a/src/vs/editor/contrib/wordHighlighter/wordHighlighter.ts b/src/vs/editor/contrib/wordHighlighter/wordHighlighter.ts
@@ -47,7 +47,7 @@ export function getOccurrencesAtPosition(model: ITextModel, position: Position,
 	return first<DocumentHighlight[] | null | undefined>(orderedByScore.map(provider => () => {
 		return Promise.resolve(provider.provideDocumentHighlights(model, position, token))
 			.then(undefined, onUnexpectedExternalError);
-	}), result => !arrays.isFalsyOrEmpty(result));
+	}), arrays.isNonEmptyArray);
 }
 
 interface IOccurenceAtPositionRequest {

Original file line number	Diff line number	Diff line change
`@@ -47,7 +47,7 @@ export function getOccurrencesAtPosition(model: ITextModel, position: Position,`
`47`	`47`	`return first<DocumentHighlight[] \| null \| undefined>(orderedByScore.map(provider => () => {`
`48`	`48`	`return Promise.resolve(provider.provideDocumentHighlights(model, position, token))`
`49`	`49`	`.then(undefined, onUnexpectedExternalError);`
`50`		`- }), result => !arrays.isFalsyOrEmpty(result));`
	`50`	`+ }), arrays.isNonEmptyArray);`
`51`	`51`	`}`
`52`	`52`
`53`	`53`	`interface IOccurenceAtPositionRequest {`