1 | /**
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2 | * @fileoverview A rule to ensure blank lines within blocks.
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3 | * @author Mathias Schreck <https://github.com/lo1tuma>
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4 | * @copyright 2014 Mathias Schreck. All rights reserved.
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5 | */
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6 |
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7 | ;
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8 |
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9 | //------------------------------------------------------------------------------
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10 | // Rule Definition
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11 | //------------------------------------------------------------------------------
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12 |
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13 | module.exports = function(context) {
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14 | var requirePadding = context.options[0] !== "never";
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15 |
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16 | var ALWAYS_MESSAGE = "Block must be padded by blank lines.",
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17 | NEVER_MESSAGE = "Block must not be padded by blank lines.";
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18 |
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19 | /**
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20 | * Retrieves an array of all comments defined inside the given node.
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21 | * @param {ASTNode} node The AST node.
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22 | * @returns {ASTNode[]} An array of comment nodes.
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23 | */
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24 | function getCommentsInNode(node) {
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25 | var allComments = context.getAllComments();
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26 |
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27 | return allComments.filter(function(comment) {
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28 | return node.range[0] < comment.range[0] &&
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29 | node.range[1] > comment.range[1];
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30 | });
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31 | }
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32 |
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33 | /**
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34 | * Checks if the location of a node or token is before the location of another node or token
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35 | * @param {ASTNode|Token} a The node or token to check if its location is before b.
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36 | * @param {ASTNode|Token} b The node or token which will be compared with a.
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37 | * @returns {boolean} True if a is located before b.
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38 | */
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39 | function isLocatedBefore(a, b) {
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40 | return a.range[1] < b.range[0];
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41 | }
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42 |
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43 | /**
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44 | * Checks if the given non empty block node has a blank line before its first child node.
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45 | * @param {ASTNode} node The AST node of a BlockStatement.
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46 | * @returns {boolean} Whether or not the block starts with a blank line.
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47 | */
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48 | function isBlockTopPadded(node) {
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49 | var blockStart = node.loc.start.line,
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50 | first = node.body[0],
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51 | firstLine = first.loc.start.line,
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52 | expectedFirstLine = blockStart + 2,
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53 | comments = getCommentsInNode(node),
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54 | firstComment = comments[0];
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55 |
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56 | if (firstComment && isLocatedBefore(firstComment, first)) {
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57 | firstLine = firstComment.loc.start.line;
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58 | }
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59 |
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60 | return expectedFirstLine <= firstLine;
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61 | }
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62 |
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63 | /**
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64 | * Checks if the given non empty block node has a blank line after its last child node.
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65 | * @param {ASTNode} node The AST node of a BlockStatement.
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66 | * @returns {boolean} Whether or not the block ends with a blank line.
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67 | */
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68 | function isBlockBottomPadded(node) {
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69 | var blockEnd = node.loc.end.line,
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70 | last = node.body[node.body.length - 1],
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71 | lastToken = context.getLastToken(last),
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72 | lastLine = lastToken.loc.end.line,
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73 | expectedLastLine = blockEnd - 2,
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74 | comments = getCommentsInNode(node),
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75 | lastComment = comments[comments.length - 1];
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76 |
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77 | if (lastComment && isLocatedBefore(lastToken, lastComment)) {
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78 | lastLine = lastComment.loc.end.line;
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79 | }
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80 |
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81 | return lastLine <= expectedLastLine;
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82 | }
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83 |
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84 | /**
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85 | * Checks the given BlockStatement node to be padded if the block is not empty.
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86 | * @param {ASTNode} node The AST node of a BlockStatement.
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87 | * @returns {void} undefined.
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88 | */
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89 | function checkPadding(node) {
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90 | if (node.body.length > 0) {
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91 |
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92 | var blockHasTopPadding = isBlockTopPadded(node),
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93 | blockHasBottomPadding = isBlockBottomPadded(node);
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94 |
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95 | if (requirePadding) {
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96 | if (!blockHasTopPadding) {
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97 | context.report(node, ALWAYS_MESSAGE);
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98 | }
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99 | if (!blockHasBottomPadding) {
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100 | context.report({
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101 | node: node,
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102 | loc: {line: node.loc.end.line, column: node.loc.end.column - 1 },
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103 | message: ALWAYS_MESSAGE
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104 | });
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105 | }
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106 | } else {
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107 | if (blockHasTopPadding) {
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108 | context.report(node, NEVER_MESSAGE);
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109 | }
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110 |
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111 | if (blockHasBottomPadding) {
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112 | context.report({
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113 | node: node,
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114 | loc: {line: node.loc.end.line, column: node.loc.end.column - 1 },
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115 | message: NEVER_MESSAGE
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116 | });
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117 | }
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118 | }
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119 | }
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120 | }
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121 |
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122 | return {
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123 | "BlockStatement": checkPadding
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124 | };
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125 |
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126 | };
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127 |
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128 | module.exports.schema = [
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129 | {
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130 | "enum": ["always", "never"]
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131 | }
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132 | ];
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