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/**
* @fileoverview A rule to disallow or enforce spaces inside of single line blocks.
* @author Toru Nagashima
*/
"use strict";
const util = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
type: "layout",
docs: {
description: "disallow or enforce spaces inside of blocks after opening block and before closing block",
category: "Stylistic Issues",
recommended: false,
url: "https://eslint.org/docs/rules/block-spacing"
},
fixable: "whitespace",
schema: [
{ enum: ["always", "never"] }
],
messages: {
missing: "Requires a space {{location}} '{{token}}'.",
extra: "Unexpected space(s) {{location}} '{{token}}'."
}
},
create(context) {
const always = (context.options[0] !== "never"),
messageId = always ? "missing" : "extra",
sourceCode = context.getSourceCode();
/**
* Gets the open brace token from a given node.
* @param {ASTNode} node A BlockStatement/SwitchStatement node to get.
* @returns {Token} The token of the open brace.
*/
function getOpenBrace(node) {
if (node.type === "SwitchStatement") {
if (node.cases.length > 0) {
return sourceCode.getTokenBefore(node.cases[0]);
}
return sourceCode.getLastToken(node, 1);
}
return sourceCode.getFirstToken(node);
}
/**
* Checks whether or not:
* - given tokens are on same line.
* - there is/isn't a space between given tokens.
* @param {Token} left A token to check.
* @param {Token} right The token which is next to `left`.
* @returns {boolean}
* When the option is `"always"`, `true` if there are one or more spaces between given tokens.
* When the option is `"never"`, `true` if there are not any spaces between given tokens.
* If given tokens are not on same line, it's always `true`.
*/
function isValid(left, right) {
return (
!util.isTokenOnSameLine(left, right) ||
sourceCode.isSpaceBetweenTokens(left, right) === always
);
}
/**
* Reports invalid spacing style inside braces.
* @param {ASTNode} node A BlockStatement/SwitchStatement node to get.
* @returns {void}
*/
function checkSpacingInsideBraces(node) {
// Gets braces and the first/last token of content.
const openBrace = getOpenBrace(node);
const closeBrace = sourceCode.getLastToken(node);
const firstToken = sourceCode.getTokenAfter(openBrace, { includeComments: true });
const lastToken = sourceCode.getTokenBefore(closeBrace, { includeComments: true });
// Skip if the node is invalid or empty.
if (openBrace.type !== "Punctuator" ||
openBrace.value !== "{" ||
closeBrace.type !== "Punctuator" ||
closeBrace.value !== "}" ||
firstToken === closeBrace
) {
return;
}
// Skip line comments for option never
if (!always && firstToken.type === "Line") {
return;
}
// Check.
if (!isValid(openBrace, firstToken)) {
context.report({
node,
loc: openBrace.loc.start,
messageId,
data: {
location: "after",
token: openBrace.value
},
fix(fixer) {
if (always) {
return fixer.insertTextBefore(firstToken, " ");
}
return fixer.removeRange([openBrace.range[1], firstToken.range[0]]);
}
});
}
if (!isValid(lastToken, closeBrace)) {
context.report({
node,
loc: closeBrace.loc.start,
messageId,
data: {
location: "before",
token: closeBrace.value
},
fix(fixer) {
if (always) {
return fixer.insertTextAfter(lastToken, " ");
}
return fixer.removeRange([lastToken.range[1], closeBrace.range[0]]);
}
});
}
}
return {
BlockStatement: checkSpacingInsideBraces,
SwitchStatement: checkSpacingInsideBraces
};
}
};