1 | /**
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2 | * @fileoverview Rule to flag use of a leading/trailing decimal point in a numeric literal
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3 | * @author James Allardice
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4 | */
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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 | // Requirements
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10 | //------------------------------------------------------------------------------
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11 |
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12 | const astUtils = require("./utils/ast-utils");
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13 |
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14 | //------------------------------------------------------------------------------
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15 | // Rule Definition
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16 | //------------------------------------------------------------------------------
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17 |
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18 | module.exports = {
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19 | meta: {
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20 | type: "suggestion",
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21 |
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22 | docs: {
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23 | description: "disallow leading or trailing decimal points in numeric literals",
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24 | category: "Best Practices",
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25 | recommended: false,
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26 | url: "https://eslint.org/docs/rules/no-floating-decimal"
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27 | },
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28 |
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29 | schema: [],
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30 | fixable: "code",
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31 | messages: {
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32 | leading: "A leading decimal point can be confused with a dot.",
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33 | trailing: "A trailing decimal point can be confused with a dot."
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34 | }
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35 | },
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36 |
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37 | create(context) {
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38 | const sourceCode = context.getSourceCode();
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39 |
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40 | return {
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41 | Literal(node) {
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42 |
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43 | if (typeof node.value === "number") {
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44 | if (node.raw.startsWith(".")) {
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45 | context.report({
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46 | node,
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47 | messageId: "leading",
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48 | fix(fixer) {
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49 | const tokenBefore = sourceCode.getTokenBefore(node);
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50 | const needsSpaceBefore = tokenBefore &&
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51 | tokenBefore.range[1] === node.range[0] &&
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52 | !astUtils.canTokensBeAdjacent(tokenBefore, `0${node.raw}`);
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53 |
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54 | return fixer.insertTextBefore(node, needsSpaceBefore ? " 0" : "0");
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55 | }
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56 | });
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57 | }
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58 | if (node.raw.indexOf(".") === node.raw.length - 1) {
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59 | context.report({
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60 | node,
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61 | messageId: "trailing",
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62 | fix: fixer => fixer.insertTextAfter(node, "0")
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63 | });
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64 | }
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65 | }
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66 | }
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67 | };
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68 |
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69 | }
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70 | };
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