useSimplifiedLogicExpression

import { Tabs, TabItem } from '@astrojs/starlight/components';

<Tabs> <TabItem label="JavaScript (and super languages)" icon="seti:javascript"> ## Summary - Rule available since: `v1.0.0` - Diagnostic Category: [`lint/complexity/useSimplifiedLogicExpression`](/reference/diagnostics#diagnostic-category) - This rule isn't recommended, so you need to enable it. - This rule has a [**safe**](/linter/#safe-fixes) fix. - The default severity of this rule is [**information**](/reference/diagnostics#information). ## How to configure ```json title="biome.json" { "linter": { "rules": { "complexity": { "useSimplifiedLogicExpression": "error" } } } }

## Description
Discard redundant terms from logical expressions.

## Examples

### Invalid

```js
const boolExp = true;
const r = true && boolExp;

<pre class="language-text"><code class="language-text">code-block.js:2:11 <a href="https://biomejs.dev/linter/rules/use-simplified-logic-expression">lint/complexity/useSimplifiedLogicExpression</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ Logical expression contains unnecessary complexity. 1 │ const boolExp = true; > 2 │ const r = true && boolExp; │ ^^^^^^^^^^^^^^^ 3 │ ℹ Safe fix: Discard redundant terms from the logical expression. 2 │ const·r·=·true·&&·boolExp; │ -------- </code></pre>

const boolExp2 = true;
const r2 = boolExp || true;

<pre class="language-text"><code class="language-text">code-block.js:2:12 <a href="https://biomejs.dev/linter/rules/use-simplified-logic-expression">lint/complexity/useSimplifiedLogicExpression</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ Logical expression contains unnecessary complexity. 1 │ const boolExp2 = true; > 2 │ const r2 = boolExp || true; │ ^^^^^^^^^^^^^^^ 3 │ ℹ Safe fix: Discard redundant terms from the logical expression. 2 │ const·r2·=·boolExp·||·true; │ ----------- </code></pre>

const nonNullExp = 123;
const r3 = null ?? nonNullExp;

<pre class="language-text"><code class="language-text">code-block.js:2:12 <a href="https://biomejs.dev/linter/rules/use-simplified-logic-expression">lint/complexity/useSimplifiedLogicExpression</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ Logical expression contains unnecessary complexity. 1 │ const nonNullExp = 123; > 2 │ const r3 = null ?? nonNullExp; │ ^^^^^^^^^^^^^^^^^^ 3 │ ℹ Safe fix: Discard redundant terms from the logical expression. 2 │ const·r3·=·null·??·nonNullExp; │ -------- </code></pre>

const boolExpr1 = true;
const boolExpr2 = false;
const r4 = !boolExpr1 || !boolExpr2;

<pre class="language-text"><code class="language-text">code-block.js:3:12 <a href="https://biomejs.dev/linter/rules/use-simplified-logic-expression">lint/complexity/useSimplifiedLogicExpression</a> FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━ ℹ Logical expression contains unnecessary complexity. 1 │ const boolExpr1 = true; 2 │ const boolExpr2 = false; > 3 │ const r4 = !boolExpr1 || !boolExpr2; │ ^^^^^^^^^^^^^^^^^^^^^^^^ 4 │ ℹ Safe fix: Reduce the complexity of the logical expression. 1 1 │ const boolExpr1 = true; 2 2 │ const boolExpr2 = false; 3 │ - const·r4·=·!boolExpr1·||·!boolExpr2; 3 │ + const·r4·=·!(boolExpr1·&&·boolExpr2); 4 4 │ </code></pre>

Valid

const boolExpr3 = true;
const boolExpr4 = false;
const r5 = !(boolExpr1 && boolExpr2);
const boolExpr5 = true;
const boolExpr6 = false;

</TabItem> </Tabs>

Valid

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