Return null for out-of-range sequence fetches, rather than throw erro…

…r. Support igv-reports, which might not have complete sequence for an exon

js/feature/render/renderFeature.js

@@ -215,11 +215,13 @@ function renderAminoAcidSequence(ctx, strand, leftExon, exon, riteExon, bpStart,
         let aaLetter
         if (undefined === aminoAcidLetter) {
 
-            const sequence = sequenceInterval.getSequence(start, end)
+            if(sequenceInterval.hasSequence(start, end)) {
 
-            if (sequence && 3 === sequence.length) {
-                const key = '+' === strand ? sequence : complementSequence(sequence.split('').reverse().join(''))
-                aaLetter = translationDict[key]
+                const sequence = sequenceInterval.getSequence(start, end)
+                if (sequence && 3 === sequence.length) {
+                    const key = '+' === strand ? sequence : complementSequence(sequence.split('').reverse().join(''))
+                    aaLetter = translationDict[key]
+                }
             }
 
         } else {

js/genome/nonIndexedFasta.js

@@ -78,7 +78,7 @@ class NonIndexedFasta {
         }
 
         if (end <= 0) {
-            return Promise.resolve(prefix)
+            return prefix
         }
 
         const seq = seqSlice.sequence

js/genome/sequenceInterval.js

@@ -8,14 +8,18 @@ class SequenceInterval extends GenomicInterval {
 
     getSequence(start, end) {
         if (start < this.start || end > this.end) {
-            throw Error("Range out of bounds")
+            return null
         }
         const offset = start - this.start
         const n = end - start
         const seq = this.features ? this.features.substring(offset, offset + n) : null
         return seq
     }
 
+    hasSequence(start, end) {
+        return start >= this.start && end <= this.end
+    }
+
 }
 
 export default SequenceInterval