ESLintESLint Formatters
ESLint comes with several built-in formatters to control the appearance of the linting results, and supports third-party formatters as well.
You can specify a formatter using the --format or -f flag on the command line. For example, --format json uses the json formatter.
The built-in formatter options are:
Example Source
Examples of each formatter were created from linting fullOfProblems.js using the .eslintrc configuration shown below.
fullOfProblems.js
function addOne(i) {
if (i != NaN) {
return i ++
} else {
return
}
};
.eslintrc:
{
"extends": "eslint:recommended",
"rules": {
"consistent-return": 2,
"indent" : [1, 4],
"no-else-return" : 1,
"semi" : [1, "always"],
"space-unary-ops" : 2
}
}
Output Examples
checkstyle
<?xml version="1.0" encoding="utf-8"?><checkstyle version="4.3"><file name="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js"><error line="1" column="10" severity="error" message="'addOne' is defined but never used. (no-unused-vars)" source="eslint.rules.no-unused-vars" /><error line="2" column="9" severity="error" message="Use the isNaN function to compare with NaN. (use-isnan)" source="eslint.rules.use-isnan" /><error line="3" column="16" severity="error" message="Unexpected space before unary operator '++'. (space-unary-ops)" source="eslint.rules.space-unary-ops" /><error line="3" column="20" severity="warning" message="Missing semicolon. (semi)" source="eslint.rules.semi" /><error line="4" column="12" severity="warning" message="Unnecessary 'else' after 'return'. (no-else-return)" source="eslint.rules.no-else-return" /><error line="5" column="1" severity="warning" message="Expected indentation of 8 spaces but found 6. (indent)" source="eslint.rules.indent" /><error line="5" column="7" severity="error" message="Function 'addOne' expected a return value. (consistent-return)" source="eslint.rules.consistent-return" /><error line="5" column="13" severity="warning" message="Missing semicolon. (semi)" source="eslint.rules.semi" /><error line="7" column="2" severity="error" message="Unnecessary semicolon. (no-extra-semi)" source="eslint.rules.no-extra-semi" /></file></checkstyle>
compact
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 1, col 10, Error - 'addOne' is defined but never used. (no-unused-vars)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 2, col 9, Error - Use the isNaN function to compare with NaN. (use-isnan)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 3, col 16, Error - Unexpected space before unary operator '++'. (space-unary-ops)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 3, col 20, Warning - Missing semicolon. (semi)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 4, col 12, Warning - Unnecessary 'else' after 'return'. (no-else-return)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 5, col 1, Warning - Expected indentation of 8 spaces but found 6. (indent)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 5, col 7, Error - Function 'addOne' expected a return value. (consistent-return)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 5, col 13, Warning - Missing semicolon. (semi)
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js: line 7, col 2, Error - Unnecessary semicolon. (no-extra-semi)
9 problems
html
jslint-xml
<?xml version="1.0" encoding="utf-8"?><jslint><file name="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js"><issue line="1" char="10" evidence="" reason="'addOne' is defined but never used. (no-unused-vars)" /><issue line="2" char="9" evidence="" reason="Use the isNaN function to compare with NaN. (use-isnan)" /><issue line="3" char="16" evidence="" reason="Unexpected space before unary operator '++'. (space-unary-ops)" /><issue line="3" char="20" evidence="" reason="Missing semicolon. (semi)" /><issue line="4" char="12" evidence="" reason="Unnecessary 'else' after 'return'. (no-else-return)" /><issue line="5" char="1" evidence="" reason="Expected indentation of 8 spaces but found 6. (indent)" /><issue line="5" char="7" evidence="" reason="Function 'addOne' expected a return value. (consistent-return)" /><issue line="5" char="13" evidence="" reason="Missing semicolon. (semi)" /><issue line="7" char="2" evidence="" reason="Unnecessary semicolon. (no-extra-semi)" /></file></jslint>
json-with-metadata
{"results":[{"filePath":"/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js","messages":[{"ruleId":"no-unused-vars","severity":2,"message":"'addOne' is defined but never used.","line":1,"column":10,"nodeType":"Identifier","messageId":"unusedVar","endLine":1,"endColumn":16},{"ruleId":"use-isnan","severity":2,"message":"Use the isNaN function to compare with NaN.","line":2,"column":9,"nodeType":"BinaryExpression","messageId":"comparisonWithNaN","endLine":2,"endColumn":17},{"ruleId":"space-unary-ops","severity":2,"message":"Unexpected space before unary operator '++'.","line":3,"column":16,"nodeType":"UpdateExpression","messageId":"unexpectedBefore","endLine":3,"endColumn":20,"fix":{"range":[57,58],"text":""}},{"ruleId":"semi","severity":1,"message":"Missing semicolon.","line":3,"column":20,"nodeType":"ReturnStatement","messageId":"missingSemi","endLine":4,"endColumn":1,"fix":{"range":[60,60],"text":";"}},{"ruleId":"no-else-return","severity":1,"message":"Unnecessary 'else' after 'return'.","line":4,"column":12,"nodeType":"BlockStatement","messageId":"unexpected","endLine":6,"endColumn":6,"fix":{"range":[0,94],"text":"function addOne(i) {\n if (i != NaN) {\n return i ++\n } \n return\n \n}"}},{"ruleId":"indent","severity":1,"message":"Expected indentation of 8 spaces but found 6.","line":5,"column":1,"nodeType":"Keyword","messageId":"wrongIndentation","endLine":5,"endColumn":7,"fix":{"range":[74,80],"text":" "}},{"ruleId":"consistent-return","severity":2,"message":"Function 'addOne' expected a return value.","line":5,"column":7,"nodeType":"ReturnStatement","messageId":"missingReturnValue","endLine":5,"endColumn":13},{"ruleId":"semi","severity":1,"message":"Missing semicolon.","line":5,"column":13,"nodeType":"ReturnStatement","messageId":"missingSemi","endLine":6,"endColumn":1,"fix":{"range":[86,86],"text":";"}},{"ruleId":"no-extra-semi","severity":2,"message":"Unnecessary semicolon.","line":7,"column":2,"nodeType":"EmptyStatement","messageId":"unexpected","endLine":7,"endColumn":3,"fix":{"range":[93,95],"text":"}"}}],"suppressedMessages":[],"errorCount":5,"fatalErrorCount":0,"warningCount":4,"fixableErrorCount":2,"fixableWarningCount":4,"source":"function addOne(i) {\n if (i != NaN) {\n return i ++\n } else {\n return\n }\n};"}],"metadata":{"rulesMeta":{"no-else-return":{"type":"suggestion","docs":{"description":"disallow `else` blocks after `return` statements in `if` statements","recommended":false,"url":"https://eslint.org/docs/rules/no-else-return"},"schema":[{"type":"object","properties":{"allowElseIf":{"type":"boolean","default":true}},"additionalProperties":false}],"fixable":"code","messages":{"unexpected":"Unnecessary 'else' after 'return'."}},"indent":{"type":"layout","docs":{"description":"enforce consistent indentation","recommended":false,"url":"https://eslint.org/docs/rules/indent"},"fixable":"whitespace","schema":[{"oneOf":[{"enum":["tab"]},{"type":"integer","minimum":0}]},{"type":"object","properties":{"SwitchCase":{"type":"integer","minimum":0,"default":0},"VariableDeclarator":{"oneOf":[{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},{"type":"object","properties":{"var":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},"let":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},"const":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]}},"additionalProperties":false}]},"outerIIFEBody":{"oneOf":[{"type":"integer","minimum":0},{"enum":["off"]}]},"MemberExpression":{"oneOf":[{"type":"integer","minimum":0},{"enum":["off"]}]},"FunctionDeclaration":{"type":"object","properties":{"parameters":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},"body":{"type":"integer","minimum":0}},"additionalProperties":false},"FunctionExpression":{"type":"object","properties":{"parameters":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},"body":{"type":"integer","minimum":0}},"additionalProperties":false},"StaticBlock":{"type":"object","properties":{"body":{"type":"integer","minimum":0}},"additionalProperties":false},"CallExpression":{"type":"object","properties":{"arguments":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]}},"additionalProperties":false},"ArrayExpression":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},"ObjectExpression":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},"ImportDeclaration":{"oneOf":[{"type":"integer","minimum":0},{"enum":["first","off"]}]},"flatTernaryExpressions":{"type":"boolean","default":false},"offsetTernaryExpressions":{"type":"boolean","default":false},"ignoredNodes":{"type":"array","items":{"type":"string","not":{"pattern":":exit$"}}},"ignoreComments":{"type":"boolean","default":false}},"additionalProperties":false}],"messages":{"wrongIndentation":"Expected indentation of but found ."}},"space-unary-ops":{"type":"layout","docs":{"description":"enforce consistent spacing before or after unary operators","recommended":false,"url":"https://eslint.org/docs/rules/space-unary-ops"},"fixable":"whitespace","schema":[{"type":"object","properties":{"words":{"type":"boolean","default":true},"nonwords":{"type":"boolean","default":false},"overrides":{"type":"object","additionalProperties":{"type":"boolean"}}},"additionalProperties":false}],"messages":{"unexpectedBefore":"Unexpected space before unary operator ''.","unexpectedAfter":"Unexpected space after unary operator ''.","unexpectedAfterWord":"Unexpected space after unary word operator ''.","wordOperator":"Unary word operator '' must be followed by whitespace.","operator":"Unary operator '' must be followed by whitespace.","beforeUnaryExpressions":"Space is required before unary expressions ''."}},"semi":{"type":"layout","docs":{"description":"require or disallow semicolons instead of ASI","recommended":false,"url":"https://eslint.org/docs/rules/semi"},"fixable":"code","schema":{"anyOf":[{"type":"array","items":[{"enum":["never"]},{"type":"object","properties":{"beforeStatementContinuationChars":{"enum":["always","any","never"]}},"additionalProperties":false}],"minItems":0,"maxItems":2},{"type":"array","items":[{"enum":["always"]},{"type":"object","properties":{"omitLastInOneLineBlock":{"type":"boolean"}},"additionalProperties":false}],"minItems":0,"maxItems":2}]},"messages":{"missingSemi":"Missing semicolon.","extraSemi":"Extra semicolon."}},"consistent-return":{"type":"suggestion","docs":{"description":"require `return` statements to either always or never specify values","recommended":false,"url":"https://eslint.org/docs/rules/consistent-return"},"schema":[{"type":"object","properties":{"treatUndefinedAsUnspecified":{"type":"boolean","default":false}},"additionalProperties":false}],"messages":{"missingReturn":"Expected to return a value at the end of .","missingReturnValue":" expected a return value.","unexpectedReturnValue":" expected no return value."}}}}}
json
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junit
<?xml version="1.0" encoding="utf-8"?>
<testsuites>
<testsuite package="org.eslint" time="0" tests="9" errors="9" name="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js">
<testcase time="0" name="org.eslint.no-unused-vars" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="'addOne' is defined but never used."><![CDATA[line 1, col 10, Error - 'addOne' is defined but never used. (no-unused-vars)]]></failure></testcase>
<testcase time="0" name="org.eslint.use-isnan" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Use the isNaN function to compare with NaN."><![CDATA[line 2, col 9, Error - Use the isNaN function to compare with NaN. (use-isnan)]]></failure></testcase>
<testcase time="0" name="org.eslint.space-unary-ops" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Unexpected space before unary operator '++'."><![CDATA[line 3, col 16, Error - Unexpected space before unary operator '++'. (space-unary-ops)]]></failure></testcase>
<testcase time="0" name="org.eslint.semi" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Missing semicolon."><![CDATA[line 3, col 20, Warning - Missing semicolon. (semi)]]></failure></testcase>
<testcase time="0" name="org.eslint.no-else-return" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Unnecessary 'else' after 'return'."><![CDATA[line 4, col 12, Warning - Unnecessary 'else' after 'return'. (no-else-return)]]></failure></testcase>
<testcase time="0" name="org.eslint.indent" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Expected indentation of 8 spaces but found 6."><![CDATA[line 5, col 1, Warning - Expected indentation of 8 spaces but found 6. (indent)]]></failure></testcase>
<testcase time="0" name="org.eslint.consistent-return" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Function 'addOne' expected a return value."><![CDATA[line 5, col 7, Error - Function 'addOne' expected a return value. (consistent-return)]]></failure></testcase>
<testcase time="0" name="org.eslint.semi" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Missing semicolon."><![CDATA[line 5, col 13, Warning - Missing semicolon. (semi)]]></failure></testcase>
<testcase time="0" name="org.eslint.no-extra-semi" classname="/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems"><failure message="Unnecessary semicolon."><![CDATA[line 7, col 2, Error - Unnecessary semicolon. (no-extra-semi)]]></failure></testcase>
</testsuite>
</testsuites>
stylish
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js
1:10 error 'addOne' is defined but never used no-unused-vars
2:9 error Use the isNaN function to compare with NaN use-isnan
3:16 error Unexpected space before unary operator '++' space-unary-ops
3:20 warning Missing semicolon semi
4:12 warning Unnecessary 'else' after 'return' no-else-return
5:1 warning Expected indentation of 8 spaces but found 6 indent
5:7 error Function 'addOne' expected a return value consistent-return
5:13 warning Missing semicolon semi
7:2 error Unnecessary semicolon no-extra-semi
✖ 9 problems (5 errors, 4 warnings)
2 errors and 4 warnings potentially fixable with the `--fix` option.
tap
TAP version 13
1..1
not ok 1 - /var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js
---
message: '''addOne'' is defined but never used.'
severity: error
data:
line: 1
column: 10
ruleId: no-unused-vars
messages:
- message: Use the isNaN function to compare with NaN.
severity: error
data:
line: 2
column: 9
ruleId: use-isnan
- message: Unexpected space before unary operator '++'.
severity: error
data:
line: 3
column: 16
ruleId: space-unary-ops
- message: Missing semicolon.
severity: warning
data:
line: 3
column: 20
ruleId: semi
- message: Unnecessary 'else' after 'return'.
severity: warning
data:
line: 4
column: 12
ruleId: no-else-return
- message: Expected indentation of 8 spaces but found 6.
severity: warning
data:
line: 5
column: 1
ruleId: indent
- message: Function 'addOne' expected a return value.
severity: error
data:
line: 5
column: 7
ruleId: consistent-return
- message: Missing semicolon.
severity: warning
data:
line: 5
column: 13
ruleId: semi
- message: Unnecessary semicolon.
severity: error
data:
line: 7
column: 2
ruleId: no-extra-semi
...
unix
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:1:10: 'addOne' is defined but never used. [Error/no-unused-vars]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:2:9: Use the isNaN function to compare with NaN. [Error/use-isnan]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:3:16: Unexpected space before unary operator '++'. [Error/space-unary-ops]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:3:20: Missing semicolon. [Warning/semi]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:4:12: Unnecessary 'else' after 'return'. [Warning/no-else-return]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:5:1: Expected indentation of 8 spaces but found 6. [Warning/indent]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:5:7: Function 'addOne' expected a return value. [Error/consistent-return]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:5:13: Missing semicolon. [Warning/semi]
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js:7:2: Unnecessary semicolon. [Error/no-extra-semi]
9 problems
visualstudio
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(1,10): error no-unused-vars : 'addOne' is defined but never used.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(2,9): error use-isnan : Use the isNaN function to compare with NaN.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(3,16): error space-unary-ops : Unexpected space before unary operator '++'.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(3,20): warning semi : Missing semicolon.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(4,12): warning no-else-return : Unnecessary 'else' after 'return'.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(5,1): warning indent : Expected indentation of 8 spaces but found 6.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(5,7): error consistent-return : Function 'addOne' expected a return value.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(5,13): warning semi : Missing semicolon.
/var/lib/jenkins/workspace/Releases/eslint Release/eslint/fullOfProblems.js(7,2): error no-extra-semi : Unnecessary semicolon.
9 problems