noMagicNumbers
¥Summary
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规则生效日期：
v2.1.0¥Rule available since:
v2.1.0 -
诊断类别：
lint/style/noMagicNumbers¥Diagnostic Category:
lint/style/noMagicNumbers -
此规则没有修复方案。
¥This rule doesn’t have a fix.
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此规则的默认严重级别为 information。
¥The default severity of this rule is information.
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来源：
¥Sources:
¥How to configure
{ "linter": { "rules": { "style": { "noMagicNumbers": "error" } } }}¥Description
报告 “魔数” 的使用情况 - 直接使用数字，而不是将其赋值给命名常量。
¥Reports usage of “magic numbers” — numbers used directly instead of being assigned to named constants.
其目标是通过鼓励开发者将此类数字提取到命名常量中，并明确其用途，从而提高代码的可维护性和可读性。
¥Its goal is to improve code maintainability and readability by encouraging developers to extract such numbers into named constants, making their purpose explicit.
忽略：
¥It ignores:
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任何位置出现的非魔法值（例如 0、1、2、10、24、60 及其负数或 bigint 形式），包括算术表达式、函数调用等。
¥non-magic values (like 0, 1, 2, 10, 24, 60, and their negative or bigint forms) found anywhere, including arithmetic expressions, fn calls etc.
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数组索引
¥Array indices
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枚举值
¥Enum values
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变量或类属性声明中的初始值
¥Initial values in variable or class property declarations
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函数参数或解构模式中的默认值
¥Default values in function parameters or destructuring patterns
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JSON.stringify 和 parseInt 的参数（例如，
JSON.stringify(22)、parseInt("123", 8)）¥Arguments to JSON.stringify and parseInt (e.g.,
JSON.stringify(22),parseInt("123", 8)) -
位运算中的操作数（例如，
a & 7、a | 7）¥Operands in bitwise operations (e.g.,
a & 7,a | 7) -
JSX 表达式中的值（例如，
<div>{1}</div>）¥Values in JSX expressions (e.g.,
<div>{1}</div>) -
对象属性值（例如，
{ tax: 0.25 }）¥Object property values (e.g.,
{ tax: 0.25 })
¥Examples
¥Invalid
let total = price * 1.23; // Magic number for tax ratecode-block.js:1:21 lint/style/noMagicNumbers ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
ℹ Magic number detected. Extract it to a constant with a meaningful name.
> 1 │ let total = price * 1.23; // Magic number for tax rate
│ ^^^^
2 │
ℹ Code is more readable and refactoring easier when special numbers are declared as constants as it makes their meaning explicit.
¥Valid
const TAX_RATE = 1.23;let total = price * TAX_RATE;const TAX_RATE = 1.23 as const;let total = price * TAX_RATE;¥Related links
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