[Refactor] usedPropTypes: avoid switch statements

Author: ljharb

lib/util/ast.js

@@ -448,6 +448,24 @@ function isTSTypeParameterInstantiation(node) {
  return node.type === 'TSTypeParameterInstantiation';
 }
 
+function isMemberExpression(node) {
+ if (!node) { return false; }
+
+ return node.type === 'MemberExpression' || node.type === 'OptionalMemberExpression';
+}
+
+function isObjectPattern(node) {
+ if (!node) { return false; }
+
+ return node.type === 'ObjectPattern';
+}
+
+function isVariableDeclarator(node) {
+ if (!node) { return false; }
+
+ return node.type === 'VariableDeclarator';
+}
+
 module.exports = {
  findReturnStatement,
  getComponentProperties,
@@ -462,7 +480,9 @@ module.exports = {
  isFunction,
  isFunctionLike,
  isFunctionLikeExpression,
+ isMemberExpression,
  isNodeFirstInLine,
+ isObjectPattern,
  isParenthesized,
  isTSAsExpression,
  isTSFunctionType,
@@ -477,6 +497,7 @@ module.exports = {
  isTSTypeParameterInstantiation,
  isTSTypeQuery,
  isTSTypeReference,
+ isVariableDeclarator,
  traverse,
  traverseReturns,
  unwrapTSAsExpression,

lib/util/usedPropTypes.js

@@ -9,7 +9,6 @@ const values = require('object.values');
 const astUtil = require('./ast');
 const componentUtil = require('./componentUtil');
 const testReactVersion = require('./version').testReactVersion;
-const ast = require('./ast');
 const eslintUtil = require('./eslint');
 
 const getScope = eslintUtil.getScope;
@@ -164,7 +163,7 @@ function isInLifeCycleMethod(node, checkAsyncSafeLifeCycles) {
  */
 function isSetStateUpdater(node) {
  const unwrappedParentCalleeNode = astUtil.isCallExpression(node.parent)
- && ast.unwrapTSAsExpression(node.parent.callee);
+ && astUtil.unwrapTSAsExpression(node.parent.callee);
 
  return unwrappedParentCalleeNode
  && unwrappedParentCalleeNode.property
@@ -181,7 +180,7 @@ function isPropArgumentInSetStateUpdater(context, node, name) {
  while (scope) {
  const unwrappedParentCalleeNode = scope.block
  && astUtil.isCallExpression(scope.block.parent)
- && ast.unwrapTSAsExpression(scope.block.parent.callee);
+ && astUtil.unwrapTSAsExpression(scope.block.parent.callee);
  if (
  unwrappedParentCalleeNode
  && unwrappedParentCalleeNode.property
@@ -215,7 +214,7 @@ function isInClassComponent(context, node) {
 function isThisDotProps(node) {
  return !!node
  && node.type === 'MemberExpression'
- && ast.unwrapTSAsExpression(node.object).type === 'ThisExpression'
+ && astUtil.unwrapTSAsExpression(node.object).type === 'ThisExpression'
  && node.property.name === 'props';
 }
 
@@ -239,7 +238,7 @@ function hasSpreadOperator(context, node) {
  * @returns {boolean}
  */
 function isPropTypesUsageByMemberExpression(context, node, utils, checkAsyncSafeLifeCycles) {
- const unwrappedObjectNode = ast.unwrapTSAsExpression(node.object);
+ const unwrappedObjectNode = astUtil.unwrapTSAsExpression(node.object);
 
  if (isInClassComponent(context, node)) {
  // this.props.*
@@ -260,7 +259,7 @@ function isPropTypesUsageByMemberExpression(context, node, utils, checkAsyncSafe
  return false;
  }
  // props.* in function component
- return unwrappedObjectNode.name === 'props' && !ast.isAssignmentLHS(node);
+ return unwrappedObjectNode.name === 'props' && !astUtil.isAssignmentLHS(node);
 }
 
 /**
@@ -321,109 +320,91 @@ module.exports = function usedPropTypesInstructions(context, components, utils)
  let name;
  let allNames;
  let properties;
- switch (node.type) {
- case 'OptionalMemberExpression':
- case 'MemberExpression':
- name = getPropertyName(context, node, utils, checkAsyncSafeLifeCycles);
- if (name) {
- allNames = parentNames.concat(name);
- if (
- // Match props.foo.bar, don't match bar[props.foo]
- node.parent.type === 'MemberExpression'
- && node.parent.object === node
- ) {
- markPropTypesAsUsed(node.parent, allNames);
- }
- // Handle the destructuring part of `const {foo} = props.a.b`
- if (
- node.parent.type === 'VariableDeclarator'
- && node.parent.id.type === 'ObjectPattern'
- ) {
- node.parent.id.parent = node.parent; // patch for bug in eslint@4 in which ObjectPattern has no parent
- markPropTypesAsUsed(node.parent.id, allNames);
- }
-
- // const a = props.a
- if (
- node.parent.type === 'VariableDeclarator'
- && node.parent.id.type === 'Identifier'
- ) {
- propVariables.set(node.parent.id.name, allNames);
- }
- // Do not mark computed props as used.
- type = name !== '__COMPUTED_PROP__' ? 'direct' : null;
+ if (astUtil.isMemberExpression(node)) {
+ name = getPropertyName(context, node, utils, checkAsyncSafeLifeCycles);
+ if (name) {
+ allNames = parentNames.concat(name);
+ const parent = node.parent;
+ if (
+ // Match props.foo.bar, don't match bar[props.foo]
+ parent.type === 'MemberExpression'
+ && 'object' in parent
+ && parent.object === node
+ ) {
+ markPropTypesAsUsed(parent, allNames);
  }
- break;
- case 'ArrowFunctionExpression':
- case 'FunctionDeclaration':
- case 'FunctionExpression': {
- if (node.params.length === 0) {
- break;
+ // Handle the destructuring part of `const {foo} = props.a.b`
+ if (
+ astUtil.isVariableDeclarator(parent)
+ && parent.id.type === 'ObjectPattern'
+ ) {
+ parent.id.parent = parent; // patch for bug in eslint@4 in which ObjectPattern has no parent
+ markPropTypesAsUsed(parent.id, allNames);
+ }
+
+ // const a = props.a
+ if (
+ astUtil.isVariableDeclarator(parent)
+ && parent.id.type === 'Identifier'
+ ) {
+ propVariables.set(parent.id.name, allNames);
  }
+ // Do not mark computed props as used.
+ type = name !== '__COMPUTED_PROP__' ? 'direct' : null;
+ }
+ } else if (astUtil.isFunctionLike(node)) {
+ if (node.params.length > 0) {
  type = 'destructuring';
  const propParam = isSetStateUpdater(node) ? node.params[1] : node.params[0];
  properties = propParam.type === 'AssignmentPattern'
  ? propParam.left.properties
  : propParam.properties;
- break;
  }
- case 'ObjectPattern':
- type = 'destructuring';
- properties = node.properties;
- break;
- case 'TSEmptyBodyFunctionExpression':
- break;
- default:
- throw new Error(`${node.type} ASTNodes are not handled by markPropTypesAsUsed`);
+ } else if (astUtil.isObjectPattern(node)) {
+ type = 'destructuring';
+ properties = node.properties;
+ } else if (node.type !== 'TSEmptyBodyFunctionExpression') {
+ throw new Error(`${node.type} ASTNodes are not handled by markPropTypesAsUsed`);
  }
 
  const component = components.get(utils.getParentComponent(node));
  const usedPropTypes = (component && component.usedPropTypes) || [];
  let ignoreUnusedPropTypesValidation = (component && component.ignoreUnusedPropTypesValidation) || false;
 
- switch (type) {
- case 'direct': {
- // Ignore Object methods
- if (name in Object.prototype) {
- break;
- }
-
+ if (type === 'direct') {
+ // Ignore Object methods
+ if (!(name in Object.prototype)) {
  const reportedNode = node.property;
  usedPropTypes.push({
  name,
  allNames,
  node: reportedNode,
  });
- break;
  }
-  case 'destructuring': {
-  for (let k = 0, l = (properties || []).length; k < l; k++) {
-  if (hasSpreadOperator(context, properties[k]) || properties[k].computed) {
-  ignoreUnusedPropTypesValidation = true;
-  break;
-  }
-  const propName = ast.getKeyValue(context, properties[k]);
+ } else if (type === 'destructuring') {
+ for (let k = 0, l = (properties || []).length; k < l; k++) {
+ if (hasSpreadOperator(context, properties[k]) || properties[k].computed) {
+ ignoreUnusedPropTypesValidation = true;
+ break;
+ }
+ const propName = astUtil.getKeyValue(context, properties[k]);
 
-  if (!propName || properties[k].type !== 'Property') {
-  break;
-  }
+ if (!propName || properties[k].type !== 'Property') {
+ break;
+ }
 
-  usedPropTypes.push({
-  allNames: parentNames.concat([propName]),
-  name: propName,
-  node: properties[k],
-  });
+ usedPropTypes.push({
+ allNames: parentNames.concat([propName]),
+ name: propName,
+ node: properties[k],
+ });
 
- if (properties[k].value.type === 'ObjectPattern') {
- markPropTypesAsUsed(properties[k].value, parentNames.concat([propName]));
- } else if (properties[k].value.type === 'Identifier') {
- propVariables.set(properties[k].value.name, parentNames.concat(propName));
- }
+ if (properties[k].value.type === 'ObjectPattern') {
+ markPropTypesAsUsed(properties[k].value, parentNames.concat([propName]));
+ } else if (properties[k].value.type === 'Identifier') {
+ propVariables.set(properties[k].value.name, parentNames.concat(propName));
  }
- break;
  }
- default:
- break;
  }
 
  components.set(component ? component.node : node, {
@@ -484,7 +465,7 @@ module.exports = function usedPropTypesInstructions(context, components, utils)
 
  return {
  VariableDeclarator(node) {
- const unwrappedInitNode = ast.unwrapTSAsExpression(node.init);
+ const unwrappedInitNode = astUtil.unwrapTSAsExpression(node.init);
 
  // let props = this.props
  if (isThisDotProps(unwrappedInitNode) && isInClassComponent(context, node) && node.id.type === 'Identifier') {
@@ -559,7 +540,7 @@ module.exports = function usedPropTypesInstructions(context, components, utils)
  return;
  }
 
- const propVariable = propVariables.get(ast.unwrapTSAsExpression(node.object).name);
+ const propVariable = propVariables.get(astUtil.unwrapTSAsExpression(node.object).name);
  if (propVariable) {
  markPropTypesAsUsed(node, propVariable);
  }