Adding logic to filter by vulnerability severity.

src/filter.ts

@@ -0,0 +1,25 @@
+import { Changes } from './schemas'
+import { Severity, SEVERITIES } from './config'
+
+export function filterChangesBySeverity(severity: Severity, changes: Changes): Changes {
+    const severityIdx = SEVERITIES.indexOf(severity)
+
+    for (let change of changes) {
+        if (change === undefined ||
+            change.vulnerabilities === undefined ||
+            change.vulnerabilities.length === 0) {
+            continue
+        }
+        change.vulnerabilities = change.vulnerabilities.filter((vuln: any) => {
+            const vulnIdx = SEVERITIES.indexOf(vuln.severity)
+            if (vulnIdx <= severityIdx) {
+                return true
+            }
+        })
+
+    }
+
+    // don't want to deal with changes with no vulnerabilities
+    changes = changes.filter((change: any) => change.vulnerabilities.length > 0)
+    return changes
+}