Merge pull request #2996 from Microsoft/lastOrUndefinedReplacement

Replace awkward last-element selection pattern with 'lastOrUndefined'
microsoft · May 4, 2015 · 4cc1848 · 4cc1848
2 parents 3eaf2cf + d5c9857
commit 4cc1848
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Showing 11 changed files with 30 additions and 30 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -3182,7 +3182,7 @@ module ts {
 
         function getRestTypeOfSignature(signature: Signature): Type {
             if (signature.hasRestParameter) {
-                let type = getTypeOfSymbol(signature.parameters[signature.parameters.length - 1]);
+                let type = getTypeOfSymbol(lastOrUndefined(signature.parameters));
                 if (type.flags & TypeFlags.Reference && (<TypeReference>type).target === globalArrayType) {
                     return (<TypeReference>type).typeArguments[0];
                 }
@@ -5666,7 +5666,7 @@ module ts {
                         // If last parameter is contextually rest parameter get its type
                         if (indexOfParameter === (func.parameters.length - 1) &&
                             funcHasRestParameters && contextualSignature.hasRestParameter && func.parameters.length >= contextualSignature.parameters.length) {
-                            return getTypeOfSymbol(contextualSignature.parameters[contextualSignature.parameters.length - 1]);
+                            return getTypeOfSymbol(lastOrUndefined(contextualSignature.parameters));
                         }
                     }
                 }
@@ -7215,9 +7215,9 @@ module ts {
                 links.type = instantiateType(getTypeAtPosition(context, i), mapper);
             }
             if (signature.hasRestParameter && context.hasRestParameter && signature.parameters.length >= context.parameters.length) {
-                let parameter = signature.parameters[signature.parameters.length - 1];
+                let parameter = lastOrUndefined(signature.parameters);
                 let links = getSymbolLinks(parameter);
-                links.type = instantiateType(getTypeOfSymbol(context.parameters[context.parameters.length - 1]), mapper);
+                links.type = instantiateType(getTypeOfSymbol(lastOrUndefined(context.parameters)), mapper);
             }
         }
 
@@ -12829,7 +12829,7 @@ module ts {
         function checkGrammarBindingElement(node: BindingElement) {
             if (node.dotDotDotToken) {
                 let elements = (<BindingPattern>node.parent).elements;
-                if (node !== elements[elements.length - 1]) {
+                if (node !== lastOrUndefined(elements)) {
                     return grammarErrorOnNode(node, Diagnostics.A_rest_element_must_be_last_in_an_array_destructuring_pattern);
                 }
 

diff --git a/src/compiler/core.ts b/src/compiler/core.ts
@@ -470,7 +470,7 @@ module ts {
         let normalized: string[] = [];
         for (let part of parts) {
             if (part !== ".") {
-                if (part === ".." && normalized.length > 0 && normalized[normalized.length - 1] !== "..") {
+                if (part === ".." && normalized.length > 0 && lastOrUndefined(normalized) !== "..") {
                     normalized.pop();
                 }
                 else {
@@ -586,7 +586,7 @@ module ts {
     export function getRelativePathToDirectoryOrUrl(directoryPathOrUrl: string, relativeOrAbsolutePath: string, currentDirectory: string, getCanonicalFileName: (fileName: string) => string, isAbsolutePathAnUrl: boolean) {
         let pathComponents = getNormalizedPathOrUrlComponents(relativeOrAbsolutePath, currentDirectory);
         let directoryComponents = getNormalizedPathOrUrlComponents(directoryPathOrUrl, currentDirectory);
-        if (directoryComponents.length > 1 && directoryComponents[directoryComponents.length - 1] === "") {
+        if (directoryComponents.length > 1 && lastOrUndefined(directoryComponents) === "") {
             // If the directory path given was of type test/cases/ then we really need components of directory to be only till its name
             // that is  ["test", "cases", ""] needs to be actually ["test", "cases"]
             directoryComponents.length--;

diff --git a/src/compiler/emitter.js b/src/compiler/emitter.js
@@ -267,7 +267,7 @@ var ts;
                 var sourceMapNameIndexMap = {};
                 var sourceMapNameIndices = [];
                 function getSourceMapNameIndex() {
-                    return sourceMapNameIndices.length ? sourceMapNameIndices[sourceMapNameIndices.length - 1] : -1;
+                    return sourceMapNameIndices.length ? lastOrUndefined(sourceMapNameIndices) : -1;
                 }
                 // Last recorded and encoded spans
                 var lastRecordedSourceMapSpan;
@@ -5084,11 +5084,11 @@ var ts;
                 }
             }
             function hasDetachedComments(pos) {
-                return detachedCommentsInfo !== undefined && detachedCommentsInfo[detachedCommentsInfo.length - 1].nodePos === pos;
+                return detachedCommentsInfo !== undefined && lastOrUndefined(detachedCommentsInfo).nodePos === pos;
             }
             function getLeadingCommentsWithoutDetachedComments() {
                 // get the leading comments from detachedPos
-                var leadingComments = ts.getLeadingCommentRanges(currentSourceFile.text, detachedCommentsInfo[detachedCommentsInfo.length - 1].detachedCommentEndPos);
+                var leadingComments = ts.getLeadingCommentRanges(currentSourceFile.text, lastOrUndefined(detachedCommentsInfo).detachedCommentEndPos);
                 if (detachedCommentsInfo.length - 1) {
                     detachedCommentsInfo.pop();
                 }
@@ -5189,13 +5189,13 @@ var ts;
                         // All comments look like they could have been part of the copyright header.  Make
                         // sure there is at least one blank line between it and the node.  If not, it's not
                         // a copyright header.
-                        var lastCommentLine = ts.getLineOfLocalPosition(currentSourceFile, detachedComments[detachedComments.length - 1].end);
+                        var lastCommentLine = ts.getLineOfLocalPosition(currentSourceFile, lastOrUndefined(detachedComments).end);
                         var nodeLine = ts.getLineOfLocalPosition(currentSourceFile, ts.skipTrivia(currentSourceFile.text, node.pos));
                         if (nodeLine >= lastCommentLine + 2) {
                             // Valid detachedComments
                             ts.emitNewLineBeforeLeadingComments(currentSourceFile, writer, node, leadingComments);
                             ts.emitComments(currentSourceFile, writer, detachedComments, true, newLine, writeComment);
-                            var currentDetachedCommentInfo = { nodePos: node.pos, detachedCommentEndPos: detachedComments[detachedComments.length - 1].end };
+                            var currentDetachedCommentInfo = { nodePos: node.pos, detachedCommentEndPos: lastOrUndefined(detachedComments).end };
                             if (detachedCommentsInfo) {
                                 detachedCommentsInfo.push(currentDetachedCommentInfo);
                             }

diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
@@ -336,7 +336,7 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
                 let sourceMapNameIndexMap: Map<number> = {};
                 let sourceMapNameIndices: number[] = [];
                 function getSourceMapNameIndex() {
-                    return sourceMapNameIndices.length ? sourceMapNameIndices[sourceMapNameIndices.length - 1] : -1;
+                    return sourceMapNameIndices.length ? lastOrUndefined(sourceMapNameIndices) : -1;
                 }
 
                 // Last recorded and encoded spans
@@ -5890,13 +5890,13 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
             }
 
             function hasDetachedComments(pos: number) {
-                return detachedCommentsInfo !== undefined && detachedCommentsInfo[detachedCommentsInfo.length - 1].nodePos === pos;
+                return detachedCommentsInfo !== undefined && lastOrUndefined(detachedCommentsInfo).nodePos === pos;
             }
 
             function getLeadingCommentsWithoutDetachedComments() {
                 // get the leading comments from detachedPos
                 let leadingComments = getLeadingCommentRanges(currentSourceFile.text,
-                    detachedCommentsInfo[detachedCommentsInfo.length - 1].detachedCommentEndPos);
+                    lastOrUndefined(detachedCommentsInfo).detachedCommentEndPos);
                 if (detachedCommentsInfo.length - 1) {
                     detachedCommentsInfo.pop();
                 }
@@ -6017,13 +6017,13 @@ var __param = (this && this.__param) || function (paramIndex, decorator) {
                         // All comments look like they could have been part of the copyright header.  Make
                         // sure there is at least one blank line between it and the node.  If not, it's not
                         // a copyright header.
-                        let lastCommentLine = getLineOfLocalPosition(currentSourceFile, detachedComments[detachedComments.length - 1].end);
+                        let lastCommentLine = getLineOfLocalPosition(currentSourceFile, lastOrUndefined(detachedComments).end);
                         let nodeLine = getLineOfLocalPosition(currentSourceFile, skipTrivia(currentSourceFile.text, node.pos));
                         if (nodeLine >= lastCommentLine + 2) {
                             // Valid detachedComments
                             emitNewLineBeforeLeadingComments(currentSourceFile, writer, node, leadingComments);
                             emitComments(currentSourceFile, writer, detachedComments, /*trailingSeparator*/ true, newLine, writeComment);
-                            let currentDetachedCommentInfo = { nodePos: node.pos, detachedCommentEndPos: detachedComments[detachedComments.length - 1].end };
+                            let currentDetachedCommentInfo = { nodePos: node.pos, detachedCommentEndPos: lastOrUndefined(detachedComments).end };
                             if (detachedCommentsInfo) {
                                 detachedCommentsInfo.push(currentDetachedCommentInfo);
                             }

diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
@@ -1691,7 +1691,7 @@ module ts {
             do {
                 templateSpans.push(parseTemplateSpan());
             }
-            while (templateSpans[templateSpans.length - 1].literal.kind === SyntaxKind.TemplateMiddle)
+            while (lastOrUndefined(templateSpans).literal.kind === SyntaxKind.TemplateMiddle)
 
             templateSpans.end = getNodeEnd();
             template.templateSpans = templateSpans;

diff --git a/src/compiler/scanner.ts b/src/compiler/scanner.ts
@@ -522,7 +522,7 @@ module ts {
                     }
                     collecting = true;
                     if (result && result.length) {
-                        result[result.length - 1].hasTrailingNewLine = true;
+                        lastOrUndefined(result).hasTrailingNewLine = true;
                     }
                     continue;
                 case CharacterCodes.tab:
@@ -569,7 +569,7 @@ module ts {
                 default:
                     if (ch > CharacterCodes.maxAsciiCharacter && (isWhiteSpace(ch) || isLineBreak(ch))) {
                         if (result && result.length && isLineBreak(ch)) {
-                            result[result.length - 1].hasTrailingNewLine = true;
+                            lastOrUndefined(result).hasTrailingNewLine = true;
                         }
                         pos++;
                         continue;

diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
@@ -856,7 +856,7 @@ module ts {
     }
 
     export function hasRestParameters(s: SignatureDeclaration): boolean {
-        return s.parameters.length > 0 && s.parameters[s.parameters.length - 1].dotDotDotToken !== undefined;
+        return s.parameters.length > 0 && lastOrUndefined(s.parameters).dotDotDotToken !== undefined;
     }
 
     export function isLiteralKind(kind: SyntaxKind): boolean {
@@ -1362,7 +1362,7 @@ module ts {
                 let lineStartsOfS = computeLineStarts(s);
                 if (lineStartsOfS.length > 1) {
                     lineCount = lineCount + lineStartsOfS.length - 1;
-                    linePos = output.length - s.length + lineStartsOfS[lineStartsOfS.length - 1];
+                    linePos = output.length - s.length + lastOrUndefined(lineStartsOfS);
                 }
             }
         }
@@ -1727,8 +1727,8 @@ module ts {
                 output.push(((charCode >> 6) & 0B00111111) | 0B10000000);
                 output.push((charCode & 0B00111111) | 0B10000000);
             }
-            else {
-                Debug.assert(false, "Unexpected code point");
+            else {
+                Debug.assert(false, "Unexpected code point");
             }
         }
 

diff --git a/src/services/breakpoints.ts b/src/services/breakpoints.ts
@@ -446,14 +446,14 @@ module ts.BreakpointResolver {
                         // fall through.
 
                     case SyntaxKind.CatchClause:
-                        return spanInNode((<Block>node.parent).statements[(<Block>node.parent).statements.length - 1]);;
+                        return spanInNode(lastOrUndefined((<Block>node.parent).statements));;
 
                     case SyntaxKind.CaseBlock:
                         // breakpoint in last statement of the last clause
                         let caseBlock = <CaseBlock>node.parent;
-                        let lastClause = caseBlock.clauses[caseBlock.clauses.length - 1];
+                        let lastClause = lastOrUndefined(caseBlock.clauses);
                         if (lastClause) {
-                            return spanInNode(lastClause.statements[lastClause.statements.length - 1]);
+                            return spanInNode(lastOrUndefined(lastClause.statements));
                         }
                         return undefined;
 

diff --git a/src/services/formatting/formattingScanner.ts b/src/services/formatting/formattingScanner.ts
@@ -51,7 +51,7 @@ module ts.formatting {
             if (isStarted) {
                 if (trailingTrivia) {
                     Debug.assert(trailingTrivia.length !== 0);
-                    wasNewLine = trailingTrivia[trailingTrivia.length - 1].kind === SyntaxKind.NewLineTrivia;
+                    wasNewLine = lastOrUndefined(trailingTrivia).kind === SyntaxKind.NewLineTrivia;
                 }
                 else {
                     wasNewLine = false;

diff --git a/src/services/services.ts b/src/services/services.ts
@@ -4058,7 +4058,7 @@ module ts {
                     return true;
                 }
                 else if (declarations.length) {
-                    result.push(createDefinitionInfo(declarations[declarations.length - 1], symbolKind, symbolName, containerName));
+                    result.push(createDefinitionInfo(lastOrUndefined(declarations), symbolKind, symbolName, containerName));
                     return true;
                 }
 

diff --git a/src/services/utilities.ts b/src/services/utilities.ts
@@ -200,7 +200,7 @@ module ts {
     function nodeEndsWith(n: Node, expectedLastToken: SyntaxKind, sourceFile: SourceFile): boolean {
         let children = n.getChildren(sourceFile);
         if (children.length) {
-            let last = children[children.length - 1];
+            let last = lastOrUndefined(children);
             if (last.kind === expectedLastToken) {
                 return true;
             }