/**
* @fileoverview This rule shoud require or disallow spaces before or after unary operations.
* @author Marcin Kumorek
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("../ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
docs: {
description: "enforce consistent spacing before or after unary operators",
category: "Stylistic Issues",
recommended: false,
url: "https://eslint.org/docs/rules/space-unary-ops"
},
fixable: "whitespace",
schema: [
{
type: "object",
properties: {
words: {
type: "boolean"
},
nonwords: {
type: "boolean"
},
overrides: {
type: "object",
additionalProperties: {
type: "boolean"
}
}
},
additionalProperties: false
}
]
},
create(context) {
const options = context.options && Array.isArray(context.options) && context.options[0] || { words: true, nonwords: false };
const sourceCode = context.getSourceCode();
//--------------------------------------------------------------------------
// Helpers
//--------------------------------------------------------------------------
/**
* Check if the node is the first "!" in a "!!" convert to Boolean expression
* @param {ASTnode} node AST node
* @returns {boolean} Whether or not the node is first "!" in "!!"
*/
function isFirstBangInBangBangExpression(node) {
return node && node.type === "UnaryExpression" && node.argument.operator === "!" &&
node.argument && node.argument.type === "UnaryExpression" && node.argument.operator === "!";
}
/**
* Check if the node's child argument is an "ObjectExpression"
* @param {ASTnode} node AST node
* @returns {boolean} Whether or not the argument's type is "ObjectExpression"
*/
function isArgumentObjectExpression(node) {
return node.argument && node.argument.type && node.argument.type === "ObjectExpression";
}
/**
* Checks if an override exists for a given operator.
* @param {string} operator Operator
* @returns {boolean} Whether or not an override has been provided for the operator
*/
function overrideExistsForOperator(operator) {
return options.overrides && options.overrides.hasOwnProperty(operator);
}
/**
* Gets the value that the override was set to for this operator
* @param {string} operator Operator
* @returns {boolean} Whether or not an override enforces a space with this operator
*/
function overrideEnforcesSpaces(operator) {
return options.overrides[operator];
}
/**
* Verify Unary Word Operator has spaces after the word operator
* @param {ASTnode} node AST node
* @param {Object} firstToken first token from the AST node
* @param {Object} secondToken second token from the AST node
* @param {string} word The word to be used for reporting
* @returns {void}
*/
function verifyWordHasSpaces(node, firstToken, secondToken, word) {
if (secondToken.range[0] === firstToken.range[1]) {
context.report({
node,
message: "Unary word operator '{{word}}' must be followed by whitespace.",
data: {
word
},
fix(fixer) {
return fixer.insertTextAfter(firstToken, " ");
}
});
}
}
/**
* Verify Unary Word Operator doesn't have spaces after the word operator
* @param {ASTnode} node AST node
* @param {Object} firstToken first token from the AST node
* @param {Object} secondToken second token from the AST node
* @param {string} word The word to be used for reporting
* @returns {void}
*/
function verifyWordDoesntHaveSpaces(node, firstToken, secondToken, word) {
if (isArgumentObjectExpression(node)) {
if (secondToken.range[0] > firstToken.range[1]) {
context.report({
node,
message: "Unexpected space after unary word operator '{{word}}'.",
data: {
word
},
fix(fixer) {
return fixer.removeRange([firstToken.range[1], secondToken.range[0]]);
}
});
}
}
}
/**
* Check Unary Word Operators for spaces after the word operator
* @param {ASTnode} node AST node
* @param {Object} firstToken first token from the AST node
* @param {Object} secondToken second token from the AST node
* @param {string} word The word to be used for reporting
* @returns {void}
*/
function checkUnaryWordOperatorForSpaces(node, firstToken, secondToken, word) {
word = word || firstToken.value;
if (overrideExistsForOperator(word)) {
if (overrideEnforcesSpaces(word)) {
verifyWordHasSpaces(node, firstToken, secondToken, word);
} else {
verifyWordDoesntHaveSpaces(node, firstToken, secondToken, word);
}
} else if (options.words) {
verifyWordHasSpaces(node, firstToken, secondToken, word);
} else {
verifyWordDoesntHaveSpaces(node, firstToken, secondToken, word);
}
}
/**
* Verifies YieldExpressions satisfy spacing requirements
* @param {ASTnode} node AST node
* @returns {void}
*/
function checkForSpacesAfterYield(node) {
const tokens = sourceCode.getFirstTokens(node, 3),
word = "yield";
if (!node.argument || node.delegate) {
return;
}
checkUnaryWordOperatorForSpaces(node, tokens[0], tokens[1], word);
}
/**
* Verifies AwaitExpressions satisfy spacing requirements
* @param {ASTNode} node AwaitExpression AST node
* @returns {void}
*/
function checkForSpacesAfterAwait(node) {
const tokens = sourceCode.getFirstTokens(node, 3);
checkUnaryWordOperatorForSpaces(node, tokens[0], tokens[1], "await");
}
/**
* Verifies UnaryExpression, UpdateExpression and NewExpression have spaces before or after the operator
* @param {ASTnode} node AST node
* @param {Object} firstToken First token in the expression
* @param {Object} secondToken Second token in the expression
* @returns {void}
*/
function verifyNonWordsHaveSpaces(node, firstToken, secondToken) {
if (node.prefix) {
if (isFirstBangInBangBangExpression(node)) {
return;
}
if (firstToken.range[1] === secondToken.range[0]) {
context.report({
node,
message: "Unary operator '{{operator}}' must be followed by whitespace.",
data: {
operator: firstToken.value
},
fix(fixer) {
return fixer.insertTextAfter(firstToken, " ");
}
});
}
} else {
if (firstToken.range[1] === secondToken.range[0]) {
context.report({
node,
message: "Space is required before unary expressions '{{token}}'.",
data: {
token: secondToken.value
},
fix(fixer) {
return fixer.insertTextBefore(secondToken, " ");
}
});
}
}
}
/**
* Verifies UnaryExpression, UpdateExpression and NewExpression don't have spaces before or after the operator
* @param {ASTnode} node AST node
* @param {Object} firstToken First token in the expression
* @param {Object} secondToken Second token in the expression
* @returns {void}
*/
function verifyNonWordsDontHaveSpaces(node, firstToken, secondToken) {
if (node.prefix) {
if (secondToken.range[0] > firstToken.range[1]) {
context.report({
node,
message: "Unexpected space after unary operator '{{operator}}'.",
data: {
operator: firstToken.value
},
fix(fixer) {
if (astUtils.canTokensBeAdjacent(firstToken, secondToken)) {
return fixer.removeRange([firstToken.range[1], secondToken.range[0]]);
}
return null;
}
});
}
} else {
if (secondToken.range[0] > firstToken.range[1]) {
context.report({
node,
message: "Unexpected space before unary operator '{{operator}}'.",
data: {
operator: secondToken.value
},
fix(fixer) {
return fixer.removeRange([firstToken.range[1], secondToken.range[0]]);
}
});
}
}
}
/**
* Verifies UnaryExpression, UpdateExpression and NewExpression satisfy spacing requirements
* @param {ASTnode} node AST node
* @returns {void}
*/
function checkForSpaces(node) {
const tokens = node.type === "UpdateExpression" && !node.prefix
? sourceCode.getLastTokens(node, 2)
: sourceCode.getFirstTokens(node, 2);
const firstToken = tokens[0];
const secondToken = tokens[1];
if ((node.type === "NewExpression" || node.prefix) && firstToken.type === "Keyword") {
checkUnaryWordOperatorForSpaces(node, firstToken, secondToken);
return;
}
const operator = node.prefix ? tokens[0].value : tokens[1].value;
if (overrideExistsForOperator(operator)) {
if (overrideEnforcesSpaces(operator)) {
verifyNonWordsHaveSpaces(node, firstToken, secondToken);
} else {
verifyNonWordsDontHaveSpaces(node, firstToken, secondToken);
}
} else if (options.nonwords) {
verifyNonWordsHaveSpaces(node, firstToken, secondToken);
} else {
verifyNonWordsDontHaveSpaces(node, firstToken, secondToken);
}
}
//--------------------------------------------------------------------------
// Public
//--------------------------------------------------------------------------
return {
UnaryExpression: checkForSpaces,
UpdateExpression: checkForSpaces,
NewExpression: checkForSpaces,
YieldExpression: checkForSpacesAfterYield,
AwaitExpression: checkForSpacesAfterAwait
};
}
};