vue hello world项目
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/**
* @fileoverview enforce consistent line breaks inside function parentheses
* @author Teddy Katz
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
type: "layout",
docs: {
description: "enforce consistent line breaks inside function parentheses",
category: "Stylistic Issues",
recommended: false,
url: "https://eslint.org/docs/rules/function-paren-newline"
},
fixable: "whitespace",
schema: [
{
oneOf: [
{
enum: ["always", "never", "consistent", "multiline", "multiline-arguments"]
},
{
type: "object",
properties: {
minItems: {
type: "integer",
minimum: 0
}
},
additionalProperties: false
}
]
}
],
messages: {
expectedBefore: "Expected newline before ')'.",
expectedAfter: "Expected newline after '('.",
expectedBetween: "Expected newline between arguments/params.",
unexpectedBefore: "Unexpected newline before ')'.",
unexpectedAfter: "Unexpected newline after '('."
}
},
create(context) {
const sourceCode = context.getSourceCode();
const rawOption = context.options[0] || "multiline";
const multilineOption = rawOption === "multiline";
const multilineArgumentsOption = rawOption === "multiline-arguments";
const consistentOption = rawOption === "consistent";
let minItems;
if (typeof rawOption === "object") {
minItems = rawOption.minItems;
} else if (rawOption === "always") {
minItems = 0;
} else if (rawOption === "never") {
minItems = Infinity;
} else {
minItems = null;
}
//----------------------------------------------------------------------
// Helpers
//----------------------------------------------------------------------
/**
* Determines whether there should be newlines inside function parens
* @param {ASTNode[]} elements The arguments or parameters in the list
* @param {boolean} hasLeftNewline `true` if the left paren has a newline in the current code.
* @returns {boolean} `true` if there should be newlines inside the function parens
*/
function shouldHaveNewlines(elements, hasLeftNewline) {
if (multilineArgumentsOption && elements.length === 1) {
return hasLeftNewline;
}
if (multilineOption || multilineArgumentsOption) {
return elements.some((element, index) => index !== elements.length - 1 && element.loc.end.line !== elements[index + 1].loc.start.line);
}
if (consistentOption) {
return hasLeftNewline;
}
return elements.length >= minItems;
}
/**
* Validates parens
* @param {Object} parens An object with keys `leftParen` for the left paren token, and `rightParen` for the right paren token
* @param {ASTNode[]} elements The arguments or parameters in the list
* @returns {void}
*/
function validateParens(parens, elements) {
const leftParen = parens.leftParen;
const rightParen = parens.rightParen;
const tokenAfterLeftParen = sourceCode.getTokenAfter(leftParen);
const tokenBeforeRightParen = sourceCode.getTokenBefore(rightParen);
const hasLeftNewline = !astUtils.isTokenOnSameLine(leftParen, tokenAfterLeftParen);
const hasRightNewline = !astUtils.isTokenOnSameLine(tokenBeforeRightParen, rightParen);
const needsNewlines = shouldHaveNewlines(elements, hasLeftNewline);
if (hasLeftNewline && !needsNewlines) {
context.report({
node: leftParen,
messageId: "unexpectedAfter",
fix(fixer) {
return sourceCode.getText().slice(leftParen.range[1], tokenAfterLeftParen.range[0]).trim()
// If there is a comment between the ( and the first element, don't do a fix.
? null
: fixer.removeRange([leftParen.range[1], tokenAfterLeftParen.range[0]]);
}
});
} else if (!hasLeftNewline && needsNewlines) {
context.report({
node: leftParen,
messageId: "expectedAfter",
fix: fixer => fixer.insertTextAfter(leftParen, "\n")
});
}
if (hasRightNewline && !needsNewlines) {
context.report({
node: rightParen,
messageId: "unexpectedBefore",
fix(fixer) {
return sourceCode.getText().slice(tokenBeforeRightParen.range[1], rightParen.range[0]).trim()
// If there is a comment between the last element and the ), don't do a fix.
? null
: fixer.removeRange([tokenBeforeRightParen.range[1], rightParen.range[0]]);
}
});
} else if (!hasRightNewline && needsNewlines) {
context.report({
node: rightParen,
messageId: "expectedBefore",
fix: fixer => fixer.insertTextBefore(rightParen, "\n")
});
}
}
/**
* Validates a list of arguments or parameters
* @param {Object} parens An object with keys `leftParen` for the left paren token, and `rightParen` for the right paren token
* @param {ASTNode[]} elements The arguments or parameters in the list
* @returns {void}
*/
function validateArguments(parens, elements) {
const leftParen = parens.leftParen;
const tokenAfterLeftParen = sourceCode.getTokenAfter(leftParen);
const hasLeftNewline = !astUtils.isTokenOnSameLine(leftParen, tokenAfterLeftParen);
const needsNewlines = shouldHaveNewlines(elements, hasLeftNewline);
for (let i = 0; i <= elements.length - 2; i++) {
const currentElement = elements[i];
const nextElement = elements[i + 1];
const hasNewLine = currentElement.loc.end.line !== nextElement.loc.start.line;
if (!hasNewLine && needsNewlines) {
context.report({
node: currentElement,
messageId: "expectedBetween",
fix: fixer => fixer.insertTextBefore(nextElement, "\n")
});
}
}
}
/**
* Gets the left paren and right paren tokens of a node.
* @param {ASTNode} node The node with parens
* @returns {Object} An object with keys `leftParen` for the left paren token, and `rightParen` for the right paren token.
* Can also return `null` if an expression has no parens (e.g. a NewExpression with no arguments, or an ArrowFunctionExpression
* with a single parameter)
*/
function getParenTokens(node) {
switch (node.type) {
case "NewExpression":
if (!node.arguments.length && !(
astUtils.isOpeningParenToken(sourceCode.getLastToken(node, { skip: 1 })) &&
astUtils.isClosingParenToken(sourceCode.getLastToken(node))
)) {
// If the NewExpression does not have parens (e.g. `new Foo`), return null.
return null;
}
// falls through
case "CallExpression":
return {
leftParen: sourceCode.getTokenAfter(node.callee, astUtils.isOpeningParenToken),
rightParen: sourceCode.getLastToken(node)
};
case "FunctionDeclaration":
case "FunctionExpression": {
const leftParen = sourceCode.getFirstToken(node, astUtils.isOpeningParenToken);
const rightParen = node.params.length
? sourceCode.getTokenAfter(node.params[node.params.length - 1], astUtils.isClosingParenToken)
: sourceCode.getTokenAfter(leftParen);
return { leftParen, rightParen };
}
case "ArrowFunctionExpression": {
const firstToken = sourceCode.getFirstToken(node, { skip: (node.async ? 1 : 0) });
if (!astUtils.isOpeningParenToken(firstToken)) {
// If the ArrowFunctionExpression has a single param without parens, return null.
return null;
}
return {
leftParen: firstToken,
rightParen: sourceCode.getTokenBefore(node.body, astUtils.isClosingParenToken)
};
}
case "ImportExpression": {
const leftParen = sourceCode.getFirstToken(node, 1);
const rightParen = sourceCode.getLastToken(node);
return { leftParen, rightParen };
}
default:
throw new TypeError(`unexpected node with type ${node.type}`);
}
}
//----------------------------------------------------------------------
// Public
//----------------------------------------------------------------------
return {
[[
"ArrowFunctionExpression",
"CallExpression",
"FunctionDeclaration",
"FunctionExpression",
"ImportExpression",
"NewExpression"
]](node) {
const parens = getParenTokens(node);
let params;
if (node.type === "ImportExpression") {
params = [node.source];
} else if (astUtils.isFunction(node)) {
params = node.params;
} else {
params = node.arguments;
}
if (parens) {
validateParens(parens, params);
if (multilineArgumentsOption) {
validateArguments(parens, params);
}
}
}
};
}
};