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node_modules/eslint-plugin-react/lib/rules/jsx-curly-brace-presence.js

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+/**
+ * @fileoverview Enforce curly braces or disallow unnecessary curly brace in JSX
+ * @author Jacky Ho
+ * @author Simon Lydell
+ */
+
+'use strict';
+
+const arrayIncludes = require('array-includes');
+
+const docsUrl = require('../util/docsUrl');
+const jsxUtil = require('../util/jsx');
+
+// ------------------------------------------------------------------------------
+// Constants
+// ------------------------------------------------------------------------------
+
+const OPTION_ALWAYS = 'always';
+const OPTION_NEVER = 'never';
+const OPTION_IGNORE = 'ignore';
+
+const OPTION_VALUES = [
+  OPTION_ALWAYS,
+  OPTION_NEVER,
+  OPTION_IGNORE
+];
+const DEFAULT_CONFIG = {props: OPTION_NEVER, children: OPTION_NEVER};
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    docs: {
+      description:
+        'Disallow unnecessary JSX expressions when literals alone are sufficient ' +
+          'or enfore JSX expressions on literals in JSX children or attributes',
+      category: 'Stylistic Issues',
+      recommended: false,
+      url: docsUrl('jsx-curly-brace-presence')
+    },
+    fixable: 'code',
+
+    schema: [
+      {
+        oneOf: [
+          {
+            type: 'object',
+            properties: {
+              props: {enum: OPTION_VALUES},
+              children: {enum: OPTION_VALUES}
+            },
+            additionalProperties: false
+          },
+          {
+            enum: OPTION_VALUES
+          }
+        ]
+      }
+    ]
+  },
+
+  create(context) {
+    const ruleOptions = context.options[0];
+    const userConfig = typeof ruleOptions === 'string' ?
+      {props: ruleOptions, children: ruleOptions} :
+      Object.assign({}, DEFAULT_CONFIG, ruleOptions);
+
+    function containsLineTerminators(rawStringValue) {
+      return /[\n\r\u2028\u2029]/.test(rawStringValue);
+    }
+
+    function containsBackslash(rawStringValue) {
+      return arrayIncludes(rawStringValue, '\\');
+    }
+
+    function containsHTMLEntity(rawStringValue) {
+      return /&[A-Za-z\d#]+;/.test(rawStringValue);
+    }
+
+    function containsDisallowedJSXTextChars(rawStringValue) {
+      return /[{<>}]/.test(rawStringValue);
+    }
+
+    function containsQuoteCharacters(value) {
+      return /['"]/.test(value);
+    }
+
+    function escapeDoubleQuotes(rawStringValue) {
+      return rawStringValue.replace(/\\"/g, '"').replace(/"/g, '\\"');
+    }
+
+    function escapeBackslashes(rawStringValue) {
+      return rawStringValue.replace(/\\/g, '\\\\');
+    }
+
+    function needToEscapeCharacterForJSX(raw) {
+      return (
+        containsBackslash(raw) ||
+        containsHTMLEntity(raw) ||
+        containsDisallowedJSXTextChars(raw)
+      );
+    }
+
+    function containsWhitespaceExpression(child) {
+      if (child.type === 'JSXExpressionContainer') {
+        const value = child.expression.value;
+        return value ? jsxUtil.isWhiteSpaces(value) : false;
+      }
+      return false;
+    }
+
+    /**
+     * Report and fix an unnecessary curly brace violation on a node
+     * @param {ASTNode} JSXExpressionNode - The AST node with an unnecessary JSX expression
+     */
+    function reportUnnecessaryCurly(JSXExpressionNode) {
+      context.report({
+        node: JSXExpressionNode,
+        message: 'Curly braces are unnecessary here.',
+        fix(fixer) {
+          const expression = JSXExpressionNode.expression;
+          const expressionType = expression.type;
+          const parentType = JSXExpressionNode.parent.type;
+
+          let textToReplace;
+          if (parentType === 'JSXAttribute') {
+            textToReplace = `"${expressionType === 'TemplateLiteral' ?
+              expression.quasis[0].value.raw :
+              expression.raw.substring(1, expression.raw.length - 1)
+            }"`;
+          } else if (jsxUtil.isJSX(expression)) {
+            const sourceCode = context.getSourceCode();
+
+            textToReplace = sourceCode.getText(expression);
+          } else {
+            textToReplace = expressionType === 'TemplateLiteral' ?
+              expression.quasis[0].value.cooked : expression.value;
+          }
+
+          return fixer.replaceText(JSXExpressionNode, textToReplace);
+        }
+      });
+    }
+
+    function reportMissingCurly(literalNode) {
+      context.report({
+        node: literalNode,
+        message: 'Need to wrap this literal in a JSX expression.',
+        fix(fixer) {
+          // If a HTML entity name is found, bail out because it can be fixed
+          // by either using the real character or the unicode equivalent.
+          // If it contains any line terminator character, bail out as well.
+          if (
+            containsHTMLEntity(literalNode.raw) ||
+            containsLineTerminators(literalNode.raw)
+          ) {
+            return null;
+          }
+
+          const expression = literalNode.parent.type === 'JSXAttribute' ?
+            `{"${escapeDoubleQuotes(escapeBackslashes(
+              literalNode.raw.substring(1, literalNode.raw.length - 1)
+            ))}"}` :
+            `{${JSON.stringify(literalNode.value)}}`;
+
+          return fixer.replaceText(literalNode, expression);
+        }
+      });
+    }
+
+    function isWhiteSpaceLiteral(node) {
+      return node.type && node.type === 'Literal' && node.value && jsxUtil.isWhiteSpaces(node.value);
+    }
+
+    // Bail out if there is any character that needs to be escaped in JSX
+    // because escaping decreases readiblity and the original code may be more
+    // readible anyway or intentional for other specific reasons
+    function lintUnnecessaryCurly(JSXExpressionNode) {
+      const expression = JSXExpressionNode.expression;
+      const expressionType = expression.type;
+
+      if (
+        (expressionType === 'Literal' || expressionType === 'JSXText') &&
+          typeof expression.value === 'string' &&
+          !isWhiteSpaceLiteral(expression) &&
+          !needToEscapeCharacterForJSX(expression.raw) && (
+          jsxUtil.isJSX(JSXExpressionNode.parent) ||
+          !containsQuoteCharacters(expression.value)
+        )
+      ) {
+        reportUnnecessaryCurly(JSXExpressionNode);
+      } else if (
+        expressionType === 'TemplateLiteral' &&
+          expression.expressions.length === 0 &&
+          expression.quasis[0].value.raw.indexOf('\n') === -1 &&
+          !needToEscapeCharacterForJSX(expression.quasis[0].value.raw) && (
+          jsxUtil.isJSX(JSXExpressionNode.parent) ||
+          !containsQuoteCharacters(expression.quasis[0].value.cooked)
+        )
+      ) {
+        reportUnnecessaryCurly(JSXExpressionNode);
+      } else if (jsxUtil.isJSX(expression)) {
+        reportUnnecessaryCurly(JSXExpressionNode);
+      }
+    }
+
+    function areRuleConditionsSatisfied(parent, config, ruleCondition) {
+      return (
+        parent.type === 'JSXAttribute' &&
+          typeof config.props === 'string' &&
+          config.props === ruleCondition
+      ) || (
+        jsxUtil.isJSX(parent) &&
+          typeof config.children === 'string' &&
+          config.children === ruleCondition
+      );
+    }
+
+    function getAdjacentSiblings(node, children) {
+      for (let i = 1; i < children.length - 1; i++) {
+        const child = children[i];
+        if (node === child) {
+          return [children[i - 1], children[i + 1]];
+        }
+      }
+      if (node === children[0] && children[1]) {
+        return [children[1]];
+      }
+      if (node === children[children.length - 1] && children[children.length - 2]) {
+        return [children[children.length - 2]];
+      }
+      return [];
+    }
+
+    function hasAdjacentJsxExpressionContainers(node, children) {
+      const childrenExcludingWhitespaceLiteral = children.filter(child => !isWhiteSpaceLiteral(child));
+      const adjSiblings = getAdjacentSiblings(node, childrenExcludingWhitespaceLiteral);
+
+      return adjSiblings.some(x => x.type && x.type === 'JSXExpressionContainer');
+    }
+    function hasAdjacentJsx(node, children) {
+      const childrenExcludingWhitespaceLiteral = children.filter(child => !isWhiteSpaceLiteral(child));
+      const adjSiblings = getAdjacentSiblings(node, childrenExcludingWhitespaceLiteral);
+
+      return adjSiblings.some(x => x.type && arrayIncludes(['JSXExpressionContainer', 'JSXElement'], x.type));
+    }
+    function shouldCheckForUnnecessaryCurly(parent, node, config) {
+      // Bail out if the parent is a JSXAttribute & its contents aren't
+      // StringLiteral or TemplateLiteral since e.g
+      // <App prop1={<CustomEl />} prop2={<CustomEl>...</CustomEl>} />
+
+      if (
+        parent.type && parent.type === 'JSXAttribute' &&
+        (node.expression && node.expression.type &&
+          node.expression.type !== 'Literal' &&
+          node.expression.type !== 'StringLiteral' &&
+          node.expression.type !== 'TemplateLiteral')
+      ) {
+        return false;
+      }
+
+      // If there are adjacent `JsxExpressionContainer` then there is no need,
+      // to check for unnecessary curly braces.
+      if (jsxUtil.isJSX(parent) && hasAdjacentJsxExpressionContainers(node, parent.children)) {
+        return false;
+      }
+      if (containsWhitespaceExpression(node) && hasAdjacentJsx(node, parent.children)) {
+        return false;
+      }
+      if (
+        parent.children &&
+        parent.children.length === 1 &&
+        containsWhitespaceExpression(node)
+      ) {
+        return false;
+      }
+
+      return areRuleConditionsSatisfied(parent, config, OPTION_NEVER);
+    }
+
+    function shouldCheckForMissingCurly(parent, config) {
+      if (
+        parent.children &&
+        parent.children.length === 1 &&
+        containsWhitespaceExpression(parent.children[0])
+      ) {
+        return false;
+      }
+
+      return areRuleConditionsSatisfied(parent, config, OPTION_ALWAYS);
+    }
+
+    // --------------------------------------------------------------------------
+    // Public
+    // --------------------------------------------------------------------------
+
+    return {
+      JSXExpressionContainer: (node) => {
+        if (shouldCheckForUnnecessaryCurly(node.parent, node, userConfig)) {
+          lintUnnecessaryCurly(node);
+        }
+      },
+
+      'Literal, JSXText': (node) => {
+        if (shouldCheckForMissingCurly(node.parent, userConfig)) {
+          reportMissingCurly(node);
+        }
+      }
+    };
+  }
+};