Fix.

node_modules/istanbul-lib-source-maps/lib/mapped.js

@@ -0,0 +1,113 @@
+/*
+ Copyright 2015, Yahoo Inc.
+ Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
+ */
+'use strict';
+
+const { FileCoverage } = require('istanbul-lib-coverage').classes;
+
+function locString(loc) {
+    return [
+        loc.start.line,
+        loc.start.column,
+        loc.end.line,
+        loc.end.column
+    ].join(':');
+}
+
+class MappedCoverage extends FileCoverage {
+    constructor(pathOrObj) {
+        super(pathOrObj);
+
+        this.meta = {
+            last: {
+                s: 0,
+                f: 0,
+                b: 0
+            },
+            seen: {}
+        };
+    }
+
+    addStatement(loc, hits) {
+        const key = 's:' + locString(loc);
+        const { meta } = this;
+        let index = meta.seen[key];
+
+        if (index === undefined) {
+            index = meta.last.s;
+            meta.last.s += 1;
+            meta.seen[key] = index;
+            this.statementMap[index] = this.cloneLocation(loc);
+        }
+
+        this.s[index] = this.s[index] || 0;
+        this.s[index] += hits;
+        return index;
+    }
+
+    addFunction(name, decl, loc, hits) {
+        const key = 'f:' + locString(decl);
+        const { meta } = this;
+        let index = meta.seen[key];
+
+        if (index === undefined) {
+            index = meta.last.f;
+            meta.last.f += 1;
+            meta.seen[key] = index;
+            name = name || `(unknown_${index})`;
+            this.fnMap[index] = {
+                name,
+                decl: this.cloneLocation(decl),
+                loc: this.cloneLocation(loc)
+            };
+        }
+
+        this.f[index] = this.f[index] || 0;
+        this.f[index] += hits;
+        return index;
+    }
+
+    addBranch(type, loc, branchLocations, hits) {
+        const key = ['b', ...branchLocations.map(l => locString(l))].join(':');
+        const { meta } = this;
+        let index = meta.seen[key];
+        if (index === undefined) {
+            index = meta.last.b;
+            meta.last.b += 1;
+            meta.seen[key] = index;
+            this.branchMap[index] = {
+                loc,
+                type,
+                locations: branchLocations.map(l => this.cloneLocation(l))
+            };
+        }
+
+        if (!this.b[index]) {
+            this.b[index] = branchLocations.map(() => 0);
+        }
+
+        hits.forEach((hit, i) => {
+            this.b[index][i] += hit;
+        });
+        return index;
+    }
+
+    /* Returns a clone of the location object with only the attributes of interest */
+    cloneLocation(loc) {
+        return {
+            start: {
+                line: loc.start.line,
+                column: loc.start.column
+            },
+            end: {
+                line: loc.end.line,
+                column: loc.end.column
+            }
+        };
+    }
+}
+
+module.exports = {
+    MappedCoverage
+};