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Update: Add Fixer method to Linter API (#8631)
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gyandeeps committed Jun 15, 2017
1 parent 26a2daa commit eb5d12c
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Showing 4 changed files with 119 additions and 80 deletions.
31 changes: 31 additions & 0 deletions docs/developer-guide/nodejs-api.md
Expand Up @@ -147,6 +147,37 @@ console.log(code.text); // "var foo = bar;"

In this way, you can retrieve the text and AST used for the last run of `linter.verify()`.

### verifyAndFix()

This method is similar to verify except that it also runs autofixing logic, similar to the `--fix` flag on the command line. The result object will contain the autofixed code, along with any remaining linting messages for the code that were not autofixed.

```js
var Linter = require("eslint").Linter;
var linter = new Linter();

var messages = linter.verifyAndFix("var foo", {
rules: {
semi: 2
}
}, { filename: "foo.js" });
```

Output object from this method:

```js
{
fixed: true,
text: "var foo;",
messages: []
}
```

The information available is:

* `fixed` - True, if the code was fixed.
* `text` - Fixed code text (might be the same as input if no fixes were applied).
* `messages` - Collection of all messages for the given code (It has the same information as explained above under `verify` block).

## linter

The `eslint.linter` object (deprecated) is an instance of the `Linter` class as defined [above](#Linter). `eslint.linter` exists for backwards compatibility, but we do not recommend using it because any mutations to it are shared among every module that uses `eslint`. Instead, please create your own instance of `eslint.Linter`.
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80 changes: 2 additions & 78 deletions lib/cli-engine.js
Expand Up @@ -23,11 +23,9 @@ const fs = require("fs"),
Config = require("./config"),
fileEntryCache = require("file-entry-cache"),
globUtil = require("./util/glob-util"),
SourceCodeFixer = require("./util/source-code-fixer"),
validator = require("./config/config-validator"),
stringify = require("json-stable-stringify"),
hash = require("./util/hash"),

pkg = require("../package.json");

const debug = require("debug")("eslint:cli-engine");
Expand Down Expand Up @@ -132,80 +130,6 @@ function calculateStatsPerRun(results) {
});
}

/**
* Performs multiple autofix passes over the text until as many fixes as possible
* have been applied.
* @param {string} text The source text to apply fixes to.
* @param {Object} config The ESLint config object to use.
* @param {Object} options The ESLint options object to use.
* @param {string} options.filename The filename from which the text was read.
* @param {boolean} options.allowInlineConfig Flag indicating if inline comments
* should be allowed.
* @param {Linter} linter Linter context
* @returns {Object} The result of the fix operation as returned from the
* SourceCodeFixer.
* @private
*/
function multipassFix(text, config, options, linter) {
const MAX_PASSES = 10;
let messages = [],
fixedResult,
fixed = false,
passNumber = 0;

/**
* This loop continues until one of the following is true:
*
* 1. No more fixes have been applied.
* 2. Ten passes have been made.
*
* That means anytime a fix is successfully applied, there will be another pass.
* Essentially, guaranteeing a minimum of two passes.
*/
do {
passNumber++;

debug(`Linting code for ${options.filename} (pass ${passNumber})`);
messages = linter.verify(text, config, options);

debug(`Generating fixed text for ${options.filename} (pass ${passNumber})`);
fixedResult = SourceCodeFixer.applyFixes(linter.getSourceCode(), messages);

// stop if there are any syntax errors.
// 'fixedResult.output' is a empty string.
if (messages.length === 1 && messages[0].fatal) {
break;
}

// keep track if any fixes were ever applied - important for return value
fixed = fixed || fixedResult.fixed;

// update to use the fixed output instead of the original text
text = fixedResult.output;

} while (
fixedResult.fixed &&
passNumber < MAX_PASSES
);


/*
* If the last result had fixes, we need to lint again to be sure we have
* the most up-to-date information.
*/
if (fixedResult.fixed) {
fixedResult.messages = linter.verify(text, config, options);
}


// ensure the last result properly reflects if fixes were done
fixedResult.fixed = fixed;
fixedResult.output = text;

return fixedResult;

}

/**
* Processes an source code using ESLint.
* @param {string} text The source code to check.
Expand Down Expand Up @@ -269,10 +193,10 @@ function processText(text, configHelper, filename, fix, allowInlineConfig, linte
} else {

if (fix) {
fixedResult = multipassFix(text, config, {
fixedResult = linter.verifyAndFix(text, config, {
filename,
allowInlineConfig
}, linter);
});
messages = fixedResult.messages;
} else {
messages = linter.verify(text, config, {
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74 changes: 72 additions & 2 deletions lib/linter.js
Expand Up @@ -27,9 +27,11 @@ const assert = require("assert"),
Rules = require("./rules"),
timing = require("./timing"),
astUtils = require("./ast-utils"),
pkg = require("../package.json"),
SourceCodeFixer = require("./util/source-code-fixer");

pkg = require("../package.json");

const debug = require("debug")("eslint:linter");
const MAX_AUTOFIX_PASSES = 10;

//------------------------------------------------------------------------------
// Typedefs
Expand Down Expand Up @@ -1185,6 +1187,74 @@ class Linter extends EventEmitter {
getDeclaredVariables(node) {
return (this.scopeManager && this.scopeManager.getDeclaredVariables(node)) || [];
}

/**
* Performs multiple autofix passes over the text until as many fixes as possible
* have been applied.
* @param {string} text The source text to apply fixes to.
* @param {Object} config The ESLint config object to use.
* @param {Object} options The ESLint options object to use.
* @param {string} options.filename The filename from which the text was read.
* @param {boolean} options.allowInlineConfig Flag indicating if inline comments
* should be allowed.
* @returns {Object} The result of the fix operation as returned from the
* SourceCodeFixer.
*/
verifyAndFix(text, config, options) {
let messages = [],
fixedResult,
fixed = false,
passNumber = 0;

/**
* This loop continues until one of the following is true:
*
* 1. No more fixes have been applied.
* 2. Ten passes have been made.
*
* That means anytime a fix is successfully applied, there will be another pass.
* Essentially, guaranteeing a minimum of two passes.
*/
do {
passNumber++;

debug(`Linting code for ${options.filename} (pass ${passNumber})`);
messages = this.verify(text, config, options);

debug(`Generating fixed text for ${options.filename} (pass ${passNumber})`);
fixedResult = SourceCodeFixer.applyFixes(this.getSourceCode(), messages);

// stop if there are any syntax errors.
// 'fixedResult.output' is a empty string.
if (messages.length === 1 && messages[0].fatal) {
break;
}

// keep track if any fixes were ever applied - important for return value
fixed = fixed || fixedResult.fixed;

// update to use the fixed output instead of the original text
text = fixedResult.output;

} while (
fixedResult.fixed &&
passNumber < MAX_AUTOFIX_PASSES
);

/*
* If the last result had fixes, we need to lint again to be sure we have
* the most up-to-date information.
*/
if (fixedResult.fixed) {
fixedResult.messages = this.verify(text, config, options);
}

// ensure the last result properly reflects if fixes were done
fixedResult.fixed = fixed;
fixedResult.output = text;

return fixedResult;
}
}

// methods that exist on SourceCode object
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14 changes: 14 additions & 0 deletions tests/lib/linter.js
Expand Up @@ -70,4 +70,18 @@ describe("Linter", () => {
});
});
});

describe("verifyAndFix", () => {
it("Fixes the code", () => {
const linter = new Linter();
const messages = linter.verifyAndFix("var a", {
rules: {
semi: 2
}
}, { filename: "test.js" });

assert.equal(messages.output, "var a;", "Fixes were applied correctly");
assert.isTrue(messages.fixed);
});
});
});

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