feat(filters): add better way to filter/keep based on undefined attr

Makes it possible for entity whitelist rules to take the value `true` or `false` to mean "keep if present" or "discard if present".

Author: thibaudcolas

src/lib/filters/entities.js

@@ -91,10 +91,15 @@ export const shouldKeepEntityByAttribute = (
   }
 
   const isValid = Object.keys(whitelist).every((attr) => {
-    const regex = new RegExp(whitelist[attr])
-    const hasData = data.hasOwnProperty(attr)
+    const check = whitelist[attr]
 
-    return hasData && regex.test(data[attr])
+    if (typeof check === "boolean") {
+      const hasData = data.hasOwnProperty(attr)
+
+      return check ? hasData : !hasData
+    }
+
+    return new RegExp(check).test(data[attr])
   })
 
   return isValid

src/lib/filters/entities.test.js

@@ -180,6 +180,25 @@ describe("entities", () => {
       ).toBe(false)
     })
 
+    it("attribute not defined on entities", () => {
+      expect(
+        shouldKeepEntityByAttribute(
+          [
+            {
+              type: "LINK",
+              whitelist: {
+                href: "^(?!#)",
+              },
+            },
+          ],
+          "LINK",
+          {
+            url: "http://example.com",
+          },
+        ),
+      ).toBe(true)
+    })
+
     describe("multiple attributes", () => {
       it("valid", () => {
         expect(
@@ -224,24 +243,78 @@ describe("entities", () => {
       })
     })
 
-    it("attribute not defined on entities", () => {
-      expect(
-        shouldKeepEntityByAttribute(
-          [
+    describe("attribute presence", () => {
+      it("requested, absent", () => {
+        expect(
+          shouldKeepEntityByAttribute(
+            [
+              {
+                type: "LINK",
+                whitelist: {
+                  id: true,
+                },
+              },
+            ],
+            "LINK",
+            {},
+          ),
+        ).toBe(false)
+      })
+
+      it("requested, present", () => {
+        expect(
+          shouldKeepEntityByAttribute(
+            [
+              {
+                type: "LINK",
+                whitelist: {
+                  id: true,
+                },
+              },
+            ],
+            "LINK",
             {
-              type: "LINK",
-              whitelist: {
-                id: ".*",
+              id: "5",
+            },
+          ),
+        ).toBe(true)
+      })
+
+      it("requested out, absent", () => {
+        expect(
+          shouldKeepEntityByAttribute(
+            [
+              {
+                type: "LINK",
+                whitelist: {
+                  id: false,
+                },
               },
+            ],
+            "LINK",
+            {},
+          ),
+        ).toBe(true)
+      })
+
+      it("requested out, present", () => {
+        expect(
+          shouldKeepEntityByAttribute(
+            [
+              {
+                type: "LINK",
+                whitelist: {
+                  id: false,
+                },
+              },
+            ],
+            "LINK",
+            {
+              id: "5",
             },
-          ],
-          "LINK",
-          {
-            href: "#_msocom_1",
-            target: "_blank",
-          },
-        ),
-      ).toBe(false)
+          ),
+        ).toBe(false)
+      })
     })
 
     describe("defaults", () => {