Reduce duplicate code for TextChange overlaps (microsoft#22278)

Andy · web-flow · commit b90cdb222152 · 2018-03-02T10:22:52.000-08:00
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
@@ -3759,27 +3759,20 @@ namespace ts {
     }
 
     export function textSpanOverlapsWith(span: TextSpan, other: TextSpan) {
-        const overlapStart = Math.max(span.start, other.start);
-        const overlapEnd = Math.min(textSpanEnd(span), textSpanEnd(other));
-        return overlapStart < overlapEnd;
+        return textSpanOverlap(span, other) !== undefined;
     }
 
     export function textSpanOverlap(span1: TextSpan, span2: TextSpan) {
-        const overlapStart = Math.max(span1.start, span2.start);
-        const overlapEnd = Math.min(textSpanEnd(span1), textSpanEnd(span2));
-        if (overlapStart < overlapEnd) {
-            return createTextSpanFromBounds(overlapStart, overlapEnd);
-        }
-        return undefined;
+        const overlap = textSpanIntersection(span1, span2);
+        return overlap && overlap.length === 0 ? undefined : overlap;
     }
 
     export function textSpanIntersectsWithTextSpan(span: TextSpan, other: TextSpan) {
-        return other.start <= textSpanEnd(span) && textSpanEnd(other) >= span.start;
+        return decodedTextSpanIntersectsWith(span.start, span.length, other.start, other.length);
     }
 
     export function textSpanIntersectsWith(span: TextSpan, start: number, length: number) {
-        const end = start + length;
-        return start <= textSpanEnd(span) && end >= span.start;
+        return decodedTextSpanIntersectsWith(span.start, span.length, start, length);
     }
 
     export function decodedTextSpanIntersectsWith(start1: number, length1: number, start2: number, length2: number) {
@@ -3793,12 +3786,9 @@ namespace ts {
     }
 
     export function textSpanIntersection(span1: TextSpan, span2: TextSpan) {
-        const intersectStart = Math.max(span1.start, span2.start);
-        const intersectEnd = Math.min(textSpanEnd(span1), textSpanEnd(span2));
-        if (intersectStart <= intersectEnd) {
-            return createTextSpanFromBounds(intersectStart, intersectEnd);
-        }
-        return undefined;
+        const start = Math.max(span1.start, span2.start);
+        const end = Math.min(textSpanEnd(span1), textSpanEnd(span2));
+        return start <= end ? createTextSpanFromBounds(start, end) : undefined;
     }
 
     export function createTextSpan(start: number, length: number): TextSpan {
