padded-blocks.js
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/**
* @fileoverview A rule to ensure blank lines within blocks.
* @author Mathias Schreck <https://github.com/lo1tuma>
* @copyright 2014 Mathias Schreck. All rights reserved.
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = function(context) {
var requirePadding = context.options[0] !== "never";
var ALWAYS_MESSAGE = "Block must be padded by blank lines.",
NEVER_MESSAGE = "Block must not be padded by blank lines.";
/**
* Retrieves an array of all comments defined inside the given node.
* @param {ASTNode} node The AST node.
* @returns {ASTNode[]} An array of comment nodes.
*/
function getCommentsInNode(node) {
var allComments = context.getAllComments();
return allComments.filter(function(comment) {
return node.range[0] < comment.range[0] &&
node.range[1] > comment.range[1];
});
}
/**
* Checks if the location of a node or token is before the location of another node or token
* @param {ASTNode|Token} a The node or token to check if its location is before b.
* @param {ASTNode|Token} b The node or token which will be compared with a.
* @returns {boolean} True if a is located before b.
*/
function isLocatedBefore(a, b) {
return a.range[1] < b.range[0];
}
/**
* Checks if the given non empty block node has a blank line before its first child node.
* @param {ASTNode} node The AST node of a BlockStatement.
* @returns {boolean} Whether or not the block starts with a blank line.
*/
function isBlockTopPadded(node) {
var blockStart = node.loc.start.line,
first = node.body[0],
firstLine = first.loc.start.line,
expectedFirstLine = blockStart + 2,
comments = getCommentsInNode(node),
firstComment = comments[0];
if (firstComment && isLocatedBefore(firstComment, first)) {
firstLine = firstComment.loc.start.line;
}
return expectedFirstLine <= firstLine;
}
/**
* Checks if the given non empty block node has a blank line after its last child node.
* @param {ASTNode} node The AST node of a BlockStatement.
* @returns {boolean} Whether or not the block ends with a blank line.
*/
function isBlockBottomPadded(node) {
var blockEnd = node.loc.end.line,
last = node.body[node.body.length - 1],
lastToken = context.getLastToken(last),
lastLine = lastToken.loc.end.line,
expectedLastLine = blockEnd - 2,
comments = getCommentsInNode(node),
lastComment = comments[comments.length - 1];
if (lastComment && isLocatedBefore(lastToken, lastComment)) {
lastLine = lastComment.loc.end.line;
}
return lastLine <= expectedLastLine;
}
/**
* Checks the given BlockStatement node to be padded if the block is not empty.
* @param {ASTNode} node The AST node of a BlockStatement.
* @returns {void} undefined.
*/
function checkPadding(node) {
if (node.body.length > 0) {
var blockHasTopPadding = isBlockTopPadded(node),
blockHasBottomPadding = isBlockBottomPadded(node);
if (requirePadding) {
if (!blockHasTopPadding) {
context.report(node, ALWAYS_MESSAGE);
}
if (!blockHasBottomPadding) {
context.report(node, node.loc.end, ALWAYS_MESSAGE);
}
} else {
if (blockHasTopPadding) {
context.report(node, NEVER_MESSAGE);
}
if (blockHasBottomPadding) {
context.report(node, node.loc.end, NEVER_MESSAGE);
}
}
}
}
return {
"BlockStatement": checkPadding
};
};
module.exports.schema = [
{
"enum": ["always", "never"]
}
];