useConsistentUnicodeBom (JavaScript)
Summary
Section titled “Summary”- Rule available since:
v2.6.3 - Diagnostic Category:
lint/nursery/useConsistentUnicodeBom - This rule has a safe fix.
- The default severity of this rule is information.
- Sources:
- Same as
unicode-bom
- Same as
How to configure
Section titled “How to configure”{ "linter": { "rules": { "nursery": { "useConsistentUnicodeBom": "error" } } }}Description
Section titled “Description”Require or disallow a Unicode byte order mark at the beginning of a file.
A byte order mark (BOM) is the invisible U+FEFF character at the start of a file.
UTF-8 does not need a BOM, so this rule disallows it by default.
Set bom to "always" if your tools require one.
U+FEFF characters elsewhere in the file are not checked by this rule.
Embedded JavaScript in HTML, Vue, Svelte, and Astro files is checked through the containing file.
Examples
Section titled “Examples”Invalid
Section titled “Invalid”The following example starts with an invisible U+FEFF character.
const value = 1;code-block.js:1:1 lint/nursery/useConsistentUnicodeBom FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
ℹ This file starts with a Unicode byte order mark (BOM).
> 1 │ const value = 1;
│ ^
2 │
ℹ UTF-8 does not require a byte order mark.
ℹ This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.
ℹ Safe fix: Remove the Unicode byte order mark.
1 │ const·value·=·1;
│ -
const value = 1;Options
Section titled “Options”Type: "always" | "never"
Default: "never"
Whether files must start with a BOM.
Use "always" to require a BOM, including in empty files.
{ "linter": { "rules": { "nursery": { "useConsistentUnicodeBom": { "level": "on", "options": { "bom": "always" } } } } }}Invalid
Section titled “Invalid”const value = 1;code-block.js:1:1 lint/nursery/useConsistentUnicodeBom FIXABLE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
ℹ This file is missing a Unicode byte order mark (BOM).
> 1 │ const value = 1;
│
2 │
ℹ The configured BOM policy requires files to start with U+FEFF.
ℹ This rule belongs to the nursery group, which means it is not yet stable and may change in the future. Visit https://biomejs.dev/linter/#nursery for more information.
ℹ Safe fix: Insert a Unicode byte order mark.
1 │ const·value·=·1;
│ +
The following example starts with an invisible U+FEFF character.
const value = 1;See Also
Section titled “See Also”noIrregularWhitespacechecks irregular whitespace elsewhere in code.
Related links
Section titled “Related links”Sponsored by
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