Rewrite used parts of stream-filter.coffee in JS

Port stream-filter.coffee to JS and add tests, but only for the
functionality that we actually still use in the app. Following the
removal of support for real-time updates in the stream, the websocket is
only configured to filter by URI, annotation ID or reply IDs
("references") in the sidebar and standalone annotation viewer.

src/sidebar/services/stream-filter.coffee

-module.exports = class StreamFilter
-  strategies: ['include_any', 'include_all', 'exclude_any', 'exclude_all']
-
-  filter:
-      match_policy :  'include_any'
-      clauses : []
-      actions :
-        create: true
-        update: true
-        delete: true
-
-  constructor: ->
-
-  getFilter: -> return @filter
-  getMatchPolicy: -> return @filter.match_policy
-  getClauses: -> return @filter.clauses
-  getActions: -> return @filter.actions
-  getActionCreate: -> return @filter.actions.create
-  getActionUpdate: -> return @filter.actions.update
-  getActionDelete: -> return @filter.actions.delete
-
-  setMatchPolicy: (policy) ->
-    @filter.match_policy = policy
-    this
-
-  setMatchPolicyIncludeAny: ->
-    @filter.match_policy = 'include_any'
-    this
-
-  setMatchPolicyIncludeAll: ->
-    @filter.match_policy = 'include_all'
-    this
-
-  setMatchPolicyExcludeAny: ->
-    @filter.match_policy = 'exclude_any'
-    this
-
-  setMatchPolicyExcludeAll: ->
-    @filter.match_policy = 'exclude_all'
-    this
-
-  setActions: (actions) ->
-    @filter.actions = actions
-    this
-
-  setActionCreate: (action) ->
-    @filter.actions.create = action
-    this
-
-  setActionUpdate: (action) ->
-    @filter.actions.update = action
-    this
-
-  setActionDelete: (action) ->
-    @filter.actions.delete = action
-    this
-
-  noClauses: ->
-    @filter.clauses = []
-    this
-
-  addClause: (field, operator, value, case_sensitive = false, options = {}) ->
-    @filter.clauses.push
-      field: field
-      operator: operator
-      value: value
-      case_sensitive: case_sensitive
-      options: options
-    this
-
-  resetFilter: ->
-    @setMatchPolicyIncludeAny()
-    @setActionCreate(true)
-    @setActionUpdate(true)
-    @setActionDelete(true)
-    @noClauses()
-    this

src/sidebar/services/stream-filter.js

+'use strict';
+
+/**
+ * StreamFilter generates JSON-serializable configuration objects that
+ * control which real-time updates are received from the annotation service.
+ *
+ * See https://github.com/hypothesis/h/blob/master/h/streamer/filter.py
+ * for the schema.
+ */
+class StreamFilter {
+  constructor() {
+    this.resetFilter();
+  }
+
+  /**
+   * Add a matching clause to the configuration.
+   *
+   * @param field - Field to filter by
+   * @param operator - How to filter
+   * @param value - Value to match
+   * @param caseSensitive - Whether matching should be case sensitive
+   */
+  addClause(field, operator, value, caseSensitive = false) {
+    this.filter.clauses.push({
+      field,
+      operator,
+      value,
+      case_sensitive: caseSensitive,
+    });
+    return this;
+  }
+
+  /** Return the JSON-serializable filtering configuration. */
+  getFilter() {
+    return this.filter;
+  }
+
+  /** Reset the configuration to return all updates. */
+  resetFilter() {
+    this.filter = {
+      match_policy: 'include_any',
+      clauses: [],
+      actions: {
+        create: true,
+        update: true,
+        delete: true,
+      },
+    };
+    return this;
+  }
+}
+
+module.exports = StreamFilter;

src/sidebar/services/test/stream-filter-test.js

+'use strict';
+
+const StreamFilter = require('../stream-filter');
+
+describe('sidebar/services/stream-filter', () => {
+  describe('#addClause', () => {
+    [{
+      field: '/uri',
+      operator: 'one_of',
+      value: ['https://example.com', 'doi:1234'],
+    },{
+      field: '/id',
+      operator: 'exactly',
+      value: '1234',
+    },{
+      field: '/references',
+      operator: 'one_of',
+      value: ['1234', '5678'],
+    }].forEach(({ field, operator, value }) => {
+      it('generates filter configurations', () => {
+        const filter = new StreamFilter();
+
+        filter.addClause(field, operator, value);
+
+        const config = filter.getFilter();
+        assert.deepEqual(config, {
+          match_policy: 'include_any',
+          clauses: [{
+            field,
+            operator,
+            value,
+            case_sensitive: false,
+          }],
+          actions: {
+            create: true,
+            update: true,
+            delete: true,
+          },
+        });
+      });
+    });
+
+    it('is chainable', () => {
+      const filter = new StreamFilter();
+      assert.equal(filter.addClause('/id', 'exactly', '123'), filter);
+    });
+  });
+
+  describe('#resetFilter', () => {
+    it('resets the configuration', () => {
+      const filter = new StreamFilter();
+
+      filter.addClause('/uri', 'one_of', ['https://example.com']);
+      filter.resetFilter();
+
+      const config = filter.getFilter();
+      assert.deepEqual(config, {
+        match_policy: 'include_any',
+        clauses: [],
+        actions: {
+          create: true,
+          update: true,
+          delete: true,
+        },
+      });
+    });
+
+    it('is chainable', () => {
+      const filter = new StreamFilter();
+      assert.equal(filter.resetFilter(), filter);
+    });
+  });
+});