Use ?. where it represents the intended semantics (#11512)

babel · May 9, 2020 · 31b361b · 31b361b
1 parent aeb51f4
commit 31b361b
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Showing 47 changed files with 99 additions and 118 deletions.
diff --git a/packages/babel-core/src/config/files/configuration.js b/packages/babel-core/src/config/files/configuration.js
@@ -71,8 +71,9 @@ export function* findRelativeConfig(
         loc,
         envName,
         caller,
-        packageData.pkg && packageData.pkg.dirname === loc
-          ? packageToBabelConfig(packageData.pkg)
+        packageData.pkg?.dirname === loc
+          ? // $FlowIgnore - packageData.pkg is not null
+            packageToBabelConfig((packageData.pkg: ConfigFile))
           : null,
       );
     }

diff --git a/packages/babel-core/src/config/index.js b/packages/babel-core/src/config/index.js
@@ -17,7 +17,8 @@ export type { PartialConfig } from "./partial";
 
 const loadOptionsRunner = gensync<[mixed], Object | null>(function*(opts) {
   const config = yield* loadFullConfig(opts);
-  return config ? config.options : null;
+  // NOTE: We want to return "null" explicitly, while ?. alone returns undefined
+  return config?.options ?? null;
 });
 
 const maybeErrback = runner => (opts: mixed, callback: Function) => {

diff --git a/packages/babel-core/src/transform-file.js b/packages/babel-core/src/transform-file.js
@@ -25,15 +25,7 @@ type TransformFile = {
 
 const transformFileRunner = gensync<[string, ?InputOptions], FileResult | null>(
   function*(filename, opts) {
-    let options;
-    if (opts == null) {
-      options = { filename };
-    } else if (opts && typeof opts === "object") {
-      options = {
-        ...opts,
-        filename,
-      };
-    }
+    const options = { ...opts, filename };
 
     const config: ResolvedConfig | null = yield* loadConfig(options);
     if (config === null) return null;

diff --git a/packages/babel-core/src/transformation/block-hoist-plugin.js b/packages/babel-core/src/transformation/block-hoist-plugin.js
@@ -44,15 +44,15 @@ const blockHoistPlugin = {
         let hasChange = false;
         for (let i = 0; i < node.body.length; i++) {
           const bodyNode = node.body[i];
-          if (bodyNode && bodyNode._blockHoist != null) {
+          if (bodyNode?._blockHoist != null) {
             hasChange = true;
             break;
           }
         }
         if (!hasChange) return;
 
         node.body = sortBy(node.body, function(bodyNode) {
-          let priority = bodyNode && bodyNode._blockHoist;
+          let priority = bodyNode?._blockHoist;
           if (priority == null) priority = 1;
           if (priority === true) priority = 2;
 

diff --git a/packages/babel-generator/src/buffer.js b/packages/babel-generator/src/buffer.js
@@ -44,7 +44,7 @@ export default class Buffer {
       // source string since it may be arbitrarily large after all transformations
       code: this._buf.join("").trimRight(),
       map: null,
-      rawMappings: map && map.getRawMappings(),
+      rawMappings: map?.getRawMappings(),
     };
 
     if (map) {
@@ -315,10 +315,10 @@ export default class Buffer {
     const origFilename = targetObj.filename;
 
     targetObj.identifierName =
-      (prop === "start" && loc && loc.identifierName) || null;
-    targetObj.line = pos ? pos.line : null;
-    targetObj.column = pos ? pos.column : null;
-    targetObj.filename = (loc && loc.filename) || null;
+      (prop === "start" && loc?.identifierName) || null;
+    targetObj.line = pos?.line;
+    targetObj.column = pos?.column;
+    targetObj.filename = loc?.filename;
 
     // We want to skip reassigning `force` if we're re-setting the same position.
     if (

diff --git a/packages/babel-generator/src/generators/base.js b/packages/babel-generator/src/generators/base.js
@@ -21,7 +21,7 @@ export function BlockStatement(node: Object) {
   this.token("{");
   this.printInnerComments(node);
 
-  const hasDirectives = node.directives && node.directives.length;
+  const hasDirectives = node.directives?.length;
 
   if (node.body.length || hasDirectives) {
     this.newline();

diff --git a/packages/babel-generator/src/generators/modules.js b/packages/babel-generator/src/generators/modules.js
@@ -147,7 +147,7 @@ export function ImportDeclaration(node: Object) {
   }
 
   const specifiers = node.specifiers.slice(0);
-  if (specifiers && specifiers.length) {
+  if (specifiers?.length) {
     // print "special" specifiers first
     for (;;) {
       const first = specifiers[0];

diff --git a/packages/babel-generator/src/node/whitespace.js b/packages/babel-generator/src/node/whitespace.js
@@ -196,10 +196,7 @@ nodes.ObjectTypeCallProperty = function(
   node: Object,
   parent,
 ): ?WhitespaceObject {
-  if (
-    parent.callProperties[0] === node &&
-    (!parent.properties || !parent.properties.length)
-  ) {
+  if (parent.callProperties[0] === node && !parent.properties?.length) {
     return {
       before: true,
     };
@@ -209,8 +206,8 @@ nodes.ObjectTypeCallProperty = function(
 nodes.ObjectTypeIndexer = function(node: Object, parent): ?WhitespaceObject {
   if (
     parent.indexers[0] === node &&
-    (!parent.properties || !parent.properties.length) &&
-    (!parent.callProperties || !parent.callProperties.length)
+    !parent.properties?.length &&
+    !parent.callProperties?.length
   ) {
     return {
       before: true,
@@ -224,9 +221,9 @@ nodes.ObjectTypeInternalSlot = function(
 ): ?WhitespaceObject {
   if (
     parent.internalSlots[0] === node &&
-    (!parent.properties || !parent.properties.length) &&
-    (!parent.callProperties || !parent.callProperties.length) &&
-    (!parent.indexers || !parent.indexers.length)
+    !parent.properties?.length &&
+    !parent.callProperties?.length &&
+    !parent.indexers?.length
   ) {
     return {
       before: true,

diff --git a/packages/babel-generator/src/printer.js b/packages/babel-generator/src/printer.js
@@ -310,7 +310,7 @@ export default class Printer {
 
     // catch up to this nodes newline if we're behind
     const pos = loc ? loc[prop] : null;
-    if (pos && pos.line !== null) {
+    if (pos?.line != null) {
       const count = pos.line - this._buf.getCurrentLine();
 
       for (let i = 0; i < count; i++) {
@@ -360,7 +360,7 @@ export default class Printer {
 
   endTerminatorless(state: Object) {
     this._noLineTerminator = false;
-    if (state && state.printed) {
+    if (state?.printed) {
       this.dedent();
       this.newline();
       this.token(")");
@@ -380,7 +380,7 @@ export default class Printer {
       throw new ReferenceError(
         `unknown node of type ${JSON.stringify(
           node.type,
-        )} with constructor ${JSON.stringify(node && node.constructor.name)}`,
+        )} with constructor ${JSON.stringify(node?.constructor.name)}`,
       );
     }
 
@@ -463,7 +463,7 @@ export default class Printer {
   }
 
   printJoin(nodes: ?Array, parent: Object, opts = {}) {
-    if (!nodes || !nodes.length) return;
+    if (!nodes?.length) return;
 
     if (opts.indent) this.indent();
 
@@ -523,7 +523,7 @@ export default class Printer {
   }
 
   printInnerComments(node, indent = true) {
-    if (!node.innerComments || !node.innerComments.length) return;
+    if (!node.innerComments?.length) return;
     if (indent) this.indent();
     this._printComments(node.innerComments);
     if (indent) this.dedent();
@@ -606,7 +606,7 @@ export default class Printer {
         : `/*${comment.value}*/`;
 
     if (isBlockComment && this.format.indent.adjustMultilineComment) {
-      const offset = comment.loc && comment.loc.start.column;
+      const offset = comment.loc?.start.column;
       if (offset) {
         const newlineRegex = new RegExp("\\n\\s{1," + offset + "}", "g");
         val = val.replace(newlineRegex, "\n");
@@ -630,7 +630,7 @@ export default class Printer {
   }
 
   _printComments(comments?: Array<Object>, inlinePureAnnotation?: boolean) {
-    if (!comments || !comments.length) return;
+    if (!comments?.length) return;
 
     if (
       inlinePureAnnotation &&

diff --git a/packages/babel-helper-compilation-targets/src/filter-items.js b/packages/babel-helper-compilation-targets/src/filter-items.js
@@ -70,8 +70,8 @@ export function isRequired(
     excludes?: Set<string>,
   } = {},
 ) {
-  if (excludes && excludes.has(name)) return false;
-  if (includes && includes.has(name)) return true;
+  if (excludes?.has(name)) return false;
+  if (includes?.has(name)) return true;
   return !targetsSupported(targets, compatData[name]);
 }
 

diff --git a/packages/babel-helper-compilation-targets/src/index.js b/packages/babel-helper-compilation-targets/src/index.js
@@ -111,7 +111,7 @@ function getLowestVersions(browsers: Array<string>): Targets {
 }
 
 function outputDecimalWarning(decimalTargets: Array<Object>): void {
-  if (!decimalTargets || !decimalTargets.length) {
+  if (!decimalTargets?.length) {
     return;
   }
 

diff --git a/packages/babel-helpers/src/index.js b/packages/babel-helpers/src/index.js
@@ -108,7 +108,7 @@ function getHelperMetadata(file) {
 
       const binding = child.scope.getBinding(exportName);
 
-      if (binding && binding.scope.path.isProgram()) {
+      if (binding?.scope.path.isProgram()) {
         exportBindingAssignments.push(makePath(child));
       }
     },

diff --git a/packages/babel-parser/src/index.js b/packages/babel-parser/src/index.js
@@ -16,7 +16,7 @@ import "./tokenizer/context";
 import type { Expression, File } from "./types";
 
 export function parse(input: string, options?: Options): File {
-  if (options && options.sourceType === "unambiguous") {
+  if (options?.sourceType === "unambiguous") {
     options = {
       ...options,
     };
@@ -71,7 +71,7 @@ export { tokTypes };
 
 function getParser(options: ?Options, input: string): Parser {
   let cls = Parser;
-  if (options && options.plugins) {
+  if (options?.plugins) {
     validatePlugins(options.plugins);
     cls = getParserClass(options.plugins);
   }

diff --git a/packages/babel-parser/src/parser/expression.js b/packages/babel-parser/src/parser/expression.js
@@ -769,7 +769,7 @@ export default class ExpressionParser extends LValParser {
         this.raise(node.start, Errors.ImportCallArity);
       } else {
         const importArg = node.arguments[0];
-        if (importArg && importArg.type === "SpreadElement") {
+        if (importArg?.type === "SpreadElement") {
           this.raise(importArg.start, Errors.ImportCallSpreadArgument);
         }
       }

diff --git a/packages/babel-parser/src/parser/lval.js b/packages/babel-parser/src/parser/lval.js
@@ -160,9 +160,9 @@ export default class LValParser extends NodeUtils {
     let end = exprList.length;
     if (end) {
       const last = exprList[end - 1];
-      if (last && last.type === "RestElement") {
+      if (last?.type === "RestElement") {
         --end;
-      } else if (last && last.type === "SpreadElement") {
+      } else if (last?.type === "SpreadElement") {
         last.type = "RestElement";
         const arg = last.argument;
         this.toAssignable(arg);
@@ -210,7 +210,7 @@ export default class LValParser extends NodeUtils {
     this.toReferencedList(exprList, isParenthesizedExpr);
 
     for (const expr of exprList) {
-      if (expr && expr.type === "ArrayExpression") {
+      if (expr?.type === "ArrayExpression") {
         this.toReferencedListDeep(expr.elements);
       }
     }

diff --git a/packages/babel-parser/src/parser/node.js b/packages/babel-parser/src/parser/node.js
@@ -13,8 +13,8 @@ class Node implements NodeBase {
     this.start = pos;
     this.end = 0;
     this.loc = new SourceLocation(loc);
-    if (parser && parser.options.ranges) this.range = [pos, 0];
-    if (parser && parser.filename) this.loc.filename = parser.filename;
+    if (parser?.options.ranges) this.range = [pos, 0];
+    if (parser?.filename) this.loc.filename = parser.filename;
   }
 
   type: string;

diff --git a/packages/babel-parser/src/plugins/estree.js b/packages/babel-parser/src/plugins/estree.js
@@ -165,7 +165,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       if (name === "__proto__" && prop.kind === "init") {
         // Store the first redefinition's position
         if (protoRef.used) {
-          if (refExpressionErrors && refExpressionErrors.doubleProto === -1) {
+          if (refExpressionErrors?.doubleProto === -1) {
             refExpressionErrors.doubleProto = key.start;
           } else {
             this.raise(key.start, Errors.DuplicateProto);
@@ -181,7 +181,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         stmt.type === "ExpressionStatement" &&
         stmt.expression.type === "Literal" &&
         typeof stmt.expression.value === "string" &&
-        (!stmt.expression.extra || !stmt.expression.extra.parenthesized)
+        !stmt.expression.extra?.parenthesized
       );
     }
 

diff --git a/packages/babel-parser/src/plugins/flow.js b/packages/babel-parser/src/plugins/flow.js
@@ -2198,7 +2198,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
     ): $ReadOnlyArray<N.Pattern> {
       for (let i = 0; i < exprList.length; i++) {
         const expr = exprList[i];
-        if (expr && expr.type === "TypeCastExpression") {
+        if (expr?.type === "TypeCastExpression") {
           exprList[i] = this.typeCastToParameter(expr);
         }
       }
@@ -2216,7 +2216,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         if (
           expr &&
           expr.type === "TypeCastExpression" &&
-          (!expr.extra || !expr.extra.parenthesized) &&
+          !expr.extra?.parenthesized &&
           (exprList.length > 1 || !isParenthesizedExpr)
         ) {
           this.raise(expr.typeAnnotation.start, FlowErrors.TypeCastInPattern);
@@ -2665,7 +2665,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         }
       }
 
-      if ((jsx && jsx.error) || this.isRelational("<")) {
+      if (jsx?.error || this.isRelational("<")) {
         state = state || this.state.clone();
 
         let typeParameters;
@@ -2690,9 +2690,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         }, state);
 
         const arrowExpression: ?N.ArrowFunctionExpression =
-          arrow.node && arrow.node.type === "ArrowFunctionExpression"
-            ? arrow.node
-            : null;
+          arrow.node?.type === "ArrowFunctionExpression" ? arrow.node : null;
 
         if (!arrow.error && arrowExpression) return arrowExpression;
 
@@ -2702,7 +2700,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         // If the error is recoverable, we can only re-report it if there is
         // a node we can return.
 
-        if (jsx && jsx.node) {
+        if (jsx?.node) {
           /*:: invariant(jsx.failState) */
           this.state = jsx.failState;
           return jsx.node;
@@ -2714,7 +2712,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           return arrowExpression;
         }
 
-        if (jsx && jsx.thrown) throw jsx.error;
+        if (jsx?.thrown) throw jsx.error;
         if (arrow.thrown) throw arrow.error;
 
         /*:: invariant(typeParameters) */

diff --git a/packages/babel-parser/src/plugins/placeholders.js b/packages/babel-parser/src/plugins/placeholders.js
@@ -261,7 +261,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
     checkExport(node: N.ExportNamedDeclaration): void {
       const { specifiers } = node;
-      if (specifiers && specifiers.length) {
+      if (specifiers?.length) {
         node.specifiers = specifiers.filter(
           node => node.exported.type === "Placeholder",
         );