math/prefer-number-is-integer

enforce the use of Number.isInteger() instead of other checking ways

• ⚙️ This rule is included in "plugin:math/recommended".
• 🔧 The --fix option on the command line can automatically fix some of the problems reported by this rule.
• 💡 Some problems reported by this rule are manually fixable by editor suggestions.

📖 Rule Details

This rule aims to enforce the use of Number.isInteger() instead of other checking ways to determine if a value is an integer.

Number.isInteger() provides several advantages over manual integer checking:

• Type safety: Only returns true for actual numbers that are integers
• No type coercion: Doesn't convert non-numbers to numbers before checking
• Clear semantics: Explicitly designed for integer checking
• Performance: Optimized native implementation
• Edge case handling: Properly handles special values like Infinity and NaN

Why Manual Checks Are Problematic

Manual integer checks using floor, ceil, trunc, or modulo operations can be:

• Less readable and express intent poorly
• Potentially less performant due to extra mathematical operations
• Prone to edge case issues with very large numbers or special values
• Not type-safe (may coerce non-numbers)

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🔧 Options

Nothing.

📚 Further reading

• MDN - Number.isInteger()
• MDN - Math.trunc()
• MDN - Math.floor()
• MDN - Math.ceil()
• MDN - Math.round()
• MDN - Remainder (%)
• MDN - parseInt()

🚀 Version

This rule was introduced in eslint-plugin-math v0.2.0

🔍 Implementation

• Rule source
• Test source
• Test fixture sources