Merge pull request #74 from chanzuckerberg/bkmartinjr-addjest

Jest tests for TypedCrossfilter

__tests__/util/bitArray.test.js

@@ -0,0 +1,184 @@
+// jshint esversion: 6
+
+const BitArray = require("../../src/util/typedCrossfilter/bitArray");
+const defaultTestLength = 8;
+
+describe("default select state", () => {
+  test("newly created Bitarray should be deselected", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    const dim = ba.allocDimension();
+    expect(dim).toBeDefined();
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.freeDimension(dim);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+  });
+});
+
+describe("select and deselect", () => {
+  test("selectAll and deselectAll", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+    const dim1 = ba.allocDimension();
+    expect(dim1).toBeDefined();
+    ba.selectAll(dim1);
+
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    const dim2 = ba.allocDimension();
+    expect(dim2).toBeDefined();
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectAll(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    ba.deselectAll(dim1);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.deselectAll(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectAll(dim1);
+    ba.selectAll(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    ba.freeDimension(dim1);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+
+    ba.freeDimension(dim2);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+  });
+
+  test("selectOne and deselectOne", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+    const dim = ba.allocDimension();
+    expect(dim).toBeDefined();
+
+    ba.selectOne(dim, 0);
+    expect(ba.isSelected(0)).toEqual(true);
+    for (let i = 1; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.deselectOne(dim, 0);
+    for (let i = 0; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectOne(dim, 1);
+    expect(ba.isSelected(1)).toEqual(true);
+    expect(ba.isSelected(0)).toEqual(false);
+    for (let i = 2; i < defaultTestLength; i++) {
+      expect(ba.isSelected(i)).toEqual(false);
+    }
+
+    ba.selectAll(dim);
+    ba.deselectOne(dim, defaultTestLength - 1);
+    expect(ba.isSelected(defaultTestLength - 1)).toEqual(false);
+    for (let i = 0; i < defaultTestLength - 1; i++) {
+      expect(ba.isSelected(i)).toEqual(true);
+    }
+  });
+});
+
+describe("selectionCount", () => {
+  test("simple", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+    const dim1 = ba.allocDimension();
+    expect(dim1).toBeDefined();
+    const dim2 = ba.allocDimension();
+    expect(dim2).toBeDefined();
+
+    expect(ba.selectionCount).toEqual(0);
+    ba.selectAll(dim1);
+    expect(ba.selectionCount).toEqual(0);
+    ba.selectAll(dim2);
+    expect(ba.selectionCount).toEqual(defaultTestLength);
+
+    for (let i = 0; i < defaultTestLength; i++) {
+      ba.deselectOne(dim1, i);
+      expect(ba.selectionCount).toEqual(defaultTestLength - i - 1);
+      expect(ba.selectionCount).toEqual(ba.countAllOnes());
+    }
+
+    ba.freeDimension(dim1);
+    ba.freeDimension(dim2);
+  });
+});
+
+describe("fillBySelection", () => {
+  test("sets values correctly", () => {
+    const ba = new BitArray(defaultTestLength);
+    expect(ba).toBeDefined();
+    const dim = ba.allocDimension();
+    expect(dim).toBeDefined();
+
+    const arr = new Int32Array(defaultTestLength);
+    arr.fill(0);
+    const truth = new Int32Array(defaultTestLength);
+    truth.fill(0);
+
+    // initial state should be deselected
+    ba.fillBySelection(arr, 1, 0);
+    expect(arr).toEqual(expect.not.arrayContaining([1]));
+
+    // selectAll
+    ba.selectAll(dim);
+    ba.fillBySelection(arr, 1, 0);
+    expect(arr).toEqual(expect.not.arrayContaining([0]));
+
+    // deselectOne
+    ba.deselectOne(dim, 3);
+    ba.fillBySelection(arr, 1, 0);
+    truth.fill(1);
+    truth[3] = 0;
+    expect(arr).toEqual(truth);
+
+    // deselectAll
+    ba.deselectAll(dim);
+    ba.fillBySelection(arr, 1, 0);
+    truth.fill(0);
+    expect(arr).toEqual(truth);
+
+    // selectOne
+    ba.selectOne(dim, 5);
+    ba.fillBySelection(arr, 6, 1);
+    truth.fill(1);
+    truth[5] = 6;
+    expect(arr).toEqual(truth);
+
+    // should be deselected after dimension disposal
+    ba.freeDimension(dim);
+    ba.fillBySelection(arr, 3, 9);
+    truth.fill(9);
+    expect(arr).toEqual(truth);
+  });
+});

__tests__/util/positiveInterval.test.js

@@ -0,0 +1,140 @@
+// jshint esversion: 6
+
+const PositiveIntervals = require("../../src/util/typedCrossfilter/positiveIntervals");
+
+describe("canonicalize", () => {
+  test("empty", () => {
+    expect(PositiveIntervals.canonicalize([])).toEqual([]);
+  });
+
+  test("simple, already correct", () => {
+    expect(PositiveIntervals.canonicalize([[0, 1]])).toEqual([[0, 1]]);
+    expect(PositiveIntervals.canonicalize([[0, 1], [2, 3]])).toEqual([
+      [0, 1],
+      [2, 3]
+    ]);
+  });
+
+  test("non-canonical, need to be canonicalized", () => {
+    expect(PositiveIntervals.canonicalize([[0, 1], [1, 2]])).toEqual([[0, 2]]);
+    expect(PositiveIntervals.canonicalize([[1, 2], [2, 3]])).toEqual([[1, 3]]);
+  });
+});
+
+describe("union", () => {
+  test("empty range", () => {
+    expect(PositiveIntervals.union([], [])).toEqual([]);
+    expect(PositiveIntervals.union([], [[1, 2]])).toEqual([[1, 2]]);
+    expect(PositiveIntervals.union([], [[1, 2], [3, 4]])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(PositiveIntervals.union([[3, 4]], [])).toEqual([[3, 4]]);
+    expect(PositiveIntervals.union([[1, 2], [3, 4]], [])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(PositiveIntervals.union([[3, 3]], [])).toEqual([[3, 3]]);
+    expect(PositiveIntervals.union([], [[3, 3]])).toEqual([[3, 3]]);
+  });
+
+  test("simple ranges", () => {
+    expect(PositiveIntervals.union([[1, 2]], [[2, 3]])).toEqual([[1, 3]]);
+    expect(PositiveIntervals.union([[2, 3]], [[1, 2]])).toEqual([[1, 3]]);
+    expect(PositiveIntervals.union([[1, 2]], [[3, 4]])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(
+      PositiveIntervals.union([[1, 2], [3, 4]], [[6, 7], [19, 40]])
+    ).toEqual([[1, 2], [3, 4], [6, 7], [19, 40]]);
+    expect(PositiveIntervals.union([[1, 4]], [[1, 1], [3, 4]])).toEqual([
+      [1, 4]
+    ]);
+    expect(PositiveIntervals.union([[3, 3]], [[4, 4]])).toEqual([
+      [3, 3],
+      [4, 4]
+    ]);
+  });
+});
+
+describe("intersection", () => {
+  test("empty range", () => {
+    expect(PositiveIntervals.intersection([], [])).toEqual([]);
+    expect(PositiveIntervals.intersection([], [[1, 2]])).toEqual([]);
+    expect(PositiveIntervals.intersection([[1, 2]], [])).toEqual([]);
+  });
+
+  test("simple", () => {
+    expect(PositiveIntervals.intersection([[1, 2]], [[2, 3]])).toEqual([]);
+    expect(PositiveIntervals.intersection([[2, 3]], [[1, 2]])).toEqual([]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[1, 10]])).toEqual([
+      [1, 10]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[2, 8]])).toEqual([
+      [2, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[2, 8]], [[1, 10]])).toEqual([
+      [2, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[2, 12]])).toEqual([
+      [2, 10]
+    ]);
+    expect(PositiveIntervals.intersection([[2, 12]], [[1, 10]])).toEqual([
+      [2, 10]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[1, 8]])).toEqual([
+      [1, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 8]], [[1, 10]])).toEqual([
+      [1, 8]
+    ]);
+    expect(PositiveIntervals.intersection([[1, 10]], [[1, 2], [6, 9]])).toEqual(
+      [[1, 2], [6, 9]]
+    );
+    expect(PositiveIntervals.intersection([[0, 2638]], [[1363, 2638]])).toEqual(
+      [[1363, 2638]]
+    );
+    expect(PositiveIntervals.intersection([[1, 2]], [[1, 2]])).toEqual([
+      [1, 2]
+    ]);
+  });
+});
+
+describe("difference", () => {
+  test("empty", () => {
+    expect(PositiveIntervals.difference([], [])).toEqual([]);
+    expect(PositiveIntervals.difference([], [[1, 10]])).toEqual([]);
+    expect(PositiveIntervals.difference([[1, 10]], [])).toEqual([[1, 10]]);
+  });
+
+  test("simple", () => {
+    expect(PositiveIntervals.difference([[1, 2], [3, 4]], [])).toEqual([
+      [1, 2],
+      [3, 4]
+    ]);
+    expect(PositiveIntervals.difference([[1, 2], [3, 10]], [[5, 10]])).toEqual([
+      [1, 2],
+      [3, 5]
+    ]);
+    expect(PositiveIntervals.difference([[1, 2], [3, 10]], [[0, 5]])).toEqual([
+      [5, 10]
+    ]);
+    expect(
+      PositiveIntervals.difference([[0, 2638]], [[0, 1363], [2055, 2638]])
+    ).toEqual([[1363, 2055]]);
+    expect(
+      PositiveIntervals.difference([[0, 1363], [2055, 2638]], [[0, 2638]])
+    ).toEqual([]);
+    expect(PositiveIntervals.difference([[0, 10]], [[0, 1]])).toEqual([
+      [1, 10]
+    ]);
+    expect(PositiveIntervals.difference([[0, 10]], [[1, 2]])).toEqual([
+      [0, 1],
+      [2, 10]
+    ]);
+    expect(PositiveIntervals.difference([[0, 10]], [[9, 10]])).toEqual([
+      [0, 9]
+    ]);
+  });
+});

__tests__/util/typedCrossfilter.test.js

@@ -0,0 +1,276 @@
+// jshint esversion: 6
+const _ = require("lodash");
+const crossfilter = require("../../src/util/typedCrossfilter");
+
+const someData = [
+  {
+    date: "2011-11-14T16:17:54Z",
+    quantity: 2,
+    total: 190,
+    tip: 100,
+    type: "tab",
+    productIDs: ["001"]
+  },
+  {
+    date: "2011-11-14T16:20:19Z",
+    quantity: 2,
+    total: 190,
+    tip: 100,
+    type: "tab",
+    productIDs: ["001", "005"]
+  },
+  {
+    date: "2011-11-14T16:28:54Z",
+    quantity: 1,
+    total: 300,
+    tip: 200,
+    type: "visa",
+    productIDs: ["004", "005"]
+  },
+  {
+    date: "2011-11-14T16:30:43Z",
+    quantity: 2,
+    total: 90,
+    tip: 0,
+    type: "tab",
+    productIDs: ["001", "002"]
+  },
+  {
+    date: "2011-11-14T16:48:46Z",
+    quantity: 2,
+    total: 90,
+    tip: 0,
+    type: "tab",
+    productIDs: ["005"]
+  },
+  {
+    date: "2011-11-14T16:53:41Z",
+    quantity: 2,
+    total: 90,
+    tip: 0,
+    type: "tab",
+    productIDs: ["001", "004", "005"]
+  },
+  {
+    date: "2011-11-14T16:54:06Z",
+    quantity: 1,
+    total: 100,
+    tip: 0,
+    type: "cash",
+    productIDs: ["001", "002", "003", "004", "005"]
+  },
+  {
+    date: "2011-11-14T16:58:03Z",
+    quantity: 2,
+    total: 90,
+    tip: 0,
+    type: "tab",
+    productIDs: ["001"]
+  },
+  {
+    date: "2011-11-14T17:07:21Z",
+    quantity: 2,
+    total: 90,
+    tip: 0,
+    type: "tab",
+    productIDs: ["004", "005"]
+  },
+  {
+    date: "2011-11-14T17:22:59Z",
+    quantity: 2,
+    total: 90,
+    tip: 0,
+    type: "tab",
+    productIDs: ["001", "002", "004", "005"]
+  },
+  {
+    date: "2011-11-14T17:25:45Z",
+    quantity: 2,
+    total: 200,
+    tip: 0,
+    type: "cash",
+    productIDs: ["002"]
+  },
+  {
+    date: "2011-11-14T17:29:52Z",
+    quantity: 1,
+    total: 200,
+    tip: 100,
+    type: "visa",
+    productIDs: ["004"]
+  }
+];
+
+var payments = null;
+beforeEach(() => {
+  payments = crossfilter(someData);
+});
+
+describe("typedCrossfilter", () => {
+  test("alloc and free", () => {
+    expect(payments).toBeDefined();
+    expect(payments.size()).toEqual(someData.length);
+    expect(payments.all()).toEqual(someData);
+
+    const quantity = payments.dimension(r => r.quantity, Int32Array);
+    expect(quantity).toBeDefined();
+    expect(quantity.id()).toBeDefined();
+
+    quantity.dispose();
+    expect(payments.size()).toEqual(someData.length);
+    expect(payments.all()).toEqual(someData);
+  });
+
+  test("filterAll and filterNone", () => {
+    expect(payments).toBeDefined();
+    const quantity = payments.dimension(r => r.quantity, Int32Array);
+    const tip = payments.dimension(r => r.tip, Float32Array);
+    const total = payments.dimension(r => r.total, Float32Array);
+    const type = payments.dimension(r => r.type, "enum");
+
+    expect(quantity).toBeDefined();
+    expect(tip).toBeDefined();
+    expect(total).toBeDefined();
+    expect(type).toBeDefined();
+
+    // initially, all should be filtered
+    expect(payments.allFiltered().length).toEqual(payments.size());
+    expect(payments.allFiltered()).toEqual(payments.all());
+    expect(payments.countFiltered()).toEqual(someData.length);
+
+    // filterAll
+    tip.filterAll(); // should change nothing
+    expect(payments.allFiltered()).toEqual(payments.all());
+    expect(payments.countFiltered()).toEqual(someData.length);
+
+    // ditto
+    total.filterAll();
+    expect(payments.allFiltered()).toEqual(payments.all());
+    expect(payments.countFiltered()).toEqual(someData.length);
+
+    // filterNone
+    type.filterNone();
+    expect(payments.allFiltered()).toEqual([]);
+    expect(payments.countFiltered()).toEqual(0);
+
+    quantity.filterNone();
+    expect(payments.allFiltered()).toEqual([]);
+    expect(payments.countFiltered()).toEqual(0);
+
+    // invert the first none; should have no effect because type is
+    // still not filtered
+    quantity.filterAll();
+    expect(payments.allFiltered()).toEqual([]);
+    expect(payments.countFiltered()).toEqual(0);
+
+    // filter all of type; should select all
+    type.filterAll();
+    expect(payments.allFiltered()).toEqual(payments.all());
+    expect(payments.countFiltered()).toEqual(payments.size());
+  });
+
+  test("filterExact", () => {
+    expect(payments).toBeDefined();
+    const quantity = payments.dimension(r => r.quantity, Int32Array);
+    const tip = payments.dimension(r => r.tip, Float32Array);
+    const total = payments.dimension(r => r.total, Float32Array);
+    const type = payments.dimension(r => r.type, "enum");
+
+    quantity.filterExact(1);
+    expect(payments.countFiltered()).toEqual(
+      _.countBy(someData, "quantity")[1]
+    );
+    expect(payments.allFiltered()).toEqual(_.filter(someData, { quantity: 1 }));
+
+    tip.filterExact(0);
+    expect(payments.allFiltered()).toEqual(
+      _.filter(someData, { tip: 0, quantity: 1 })
+    );
+
+    type.filterExact("cash");
+    expect(payments.allFiltered()).toEqual(
+      _.filter(someData, { tip: 0, quantity: 1, type: "cash" })
+    );
+  });
+
+  test("filterRange", () => {
+    expect(payments).toBeDefined();
+    const quantity = payments.dimension(r => r.quantity, Int32Array);
+    const tip = payments.dimension(r => r.tip, Float32Array);
+    const total = payments.dimension(r => r.total, Float32Array);
+    const type = payments.dimension(r => r.type, "enum");
+
+    tip.filterRange([0, 91]);
+    expect(payments.allFiltered()).toEqual(
+      _(someData)
+        .filter(r => r.tip >= 0 && r.tip < 91)
+        .value()
+    );
+
+    tip.filterRange([0, 90]);
+    expect(payments.allFiltered()).toEqual(
+      _(someData)
+        .filter(r => r.tip >= 0 && r.tip < 90)
+        .value()
+    );
+
+    tip.filterRange([1, 90]);
+    expect(payments.allFiltered()).toEqual(
+      _(someData)
+        .filter(r => r.tip >= 1 && r.tip < 91)
+        .value()
+    );
+  });
+
+  test("filterEnum", () => {
+    expect(payments).toBeDefined();
+    const quantity = payments.dimension(r => r.quantity, Int32Array);
+    const tip = payments.dimension(r => r.tip, Float32Array);
+    const total = payments.dimension(r => r.total, Float32Array);
+    const type = payments.dimension(r => r.type, "enum");
+
+    type.filterEnum(["tab", "cash"]);
+    expect(payments.allFiltered()).toEqual(
+      _(someData)
+        .filter(r => r.type === "cash" || r.type === "tab")
+        .value()
+    );
+
+    tip.filterEnum([0, 100]);
+    expect(payments.allFiltered()).toEqual(
+      _(someData)
+        .filter(r => r.type === "cash" || r.type === "tab")
+        .filter(r => r.tip === 0 || r.tip === 100)
+        .value()
+    );
+  });
+
+  test("more than 32 dimensions", () => {
+    expect(payments).toBeDefined();
+    const quantity = payments.dimension(r => r.quantity, Int32Array);
+    const tip = payments.dimension(r => r.tip, Float32Array);
+    const total = payments.dimension(r => r.total, Float32Array);
+    const type = payments.dimension(r => r.type, "enum");
+
+    // Create a bunch of fake dimensions to ensure we can handle > 32
+    let dimMap = {};
+    for (let i = 0; i < 65; i++) {
+      dimMap[i] = payments.dimension(r => Math.random(), Float32Array);
+      expect(dimMap[i]).toBeDefined();
+      expect(dimMap[i].id()).toBeDefined();
+    }
+
+    // everything should start as selected/filtered
+    expect(payments.countFiltered()).toEqual(someData.length);
+
+    dimMap[0].filterAll();
+    dimMap[64].filterAll();
+    expect(payments.countFiltered()).toEqual(someData.length);
+
+    dimMap[33].filterNone();
+    expect(payments.allFiltered()).toEqual([]);
+
+    dimMap[33].filterAll();
+    expect(payments.allFiltered()).toEqual(someData);
+  });
+});

package.json

@@ -4,12 +4,15 @@
   "license": "MIT",
   "repository": "https://github.com/chanzuckerberg/cellxgene",
   "scripts": {
-    "build": "npm run clean && webpack --config configuration/webpack/webpack.config.prod.js",
-    "dev": "npm run clean && webpack --config configuration/webpack/webpack.config.dev.js",
+    "build":
+      "npm run clean && webpack --config configuration/webpack/webpack.config.prod.js",
+    "dev":
+      "npm run clean && webpack --config configuration/webpack/webpack.config.dev.js",
     "clean": "rimraf build",
     "start": "node server/development.js",
     "lint": "eslint src",
-    "prod": "cross-env NODE_ENV=production PORT=3000 node server/production.js"
+    "prod": "cross-env NODE_ENV=production PORT=3000 node server/production.js",
+    "test": "jest"
   },
   "engineStrict": true,
   "engines": {
@@ -90,6 +93,7 @@
     "gzip-size": "^3.0.0",
     "html-webpack-inline-source-plugin": "0.0.6",
     "html-webpack-plugin": "^2.22.0",
+    "jest": "^23.0.1",
     "jsdom": "^9.4.1",
     "json-loader": "^0.5.4",
     "nyc": "^10.0.0",
@@ -106,5 +110,8 @@
     "webpack-dev-middleware": "^1.6.1",
     "webpack-hot-middleware": "^2.12.2",
     "whatwg-fetch": "^2.0.1"
+  },
+  "jest": {
+    "testMatch": ["**/__tests__/**/?(*.)(spec|test).js?(x)"]
   }
 }

src/util/typedCrossfilter/bitArray.js

@@ -140,7 +140,7 @@ class BitArray {
     const col = dim >>> 5;
     const before = this.bitarray[col * this.length + index];
     const after = before | (1 << (dim % 32));
-    this.bitarray[col] = after;
+    this.bitarray[col * this.length + index] = after;
   }
 
   // deselect index on dimension
@@ -149,7 +149,7 @@ class BitArray {
     const col = dim >>> 5;
     const before = this.bitarray[col * this.length + index];
     const after = before & ~(1 << (dim % 32));
-    this.bitarray[col] = after;
+    this.bitarray[col * this.length + index] = after;
   }
 
   // select all indices on dimension.
@@ -214,7 +214,8 @@ class BitArray {
       const bitmask = this.bitmask[0];
       const bitarray = this.bitarray;
       for (let i = 0, len = this.length; i < len; i++) {
-        result[i] = bitarray[i] === bitmask ? selectedValue : deselectedValue;
+        result[i] =
+          bitmask && bitarray[i] === bitmask ? selectedValue : deselectedValue;
       }
     } else {
       for (let i = 0, len = this.length; i < len; i++) {

src/util/typedCrossfilter/index.js

@@ -65,7 +65,7 @@ class TypedCrossfilter {
 
   _freeDimension(id) {
     this.selection.freeDimension(id);
-    this.filters = this.filters.filter(f => f.id != id);
+    this.filters = this.filters.filter(f => f._id != id);
   }
 
   // return array of all records that are selected/filtered
@@ -105,7 +105,7 @@ class TypedCrossfilter {
 class ScalarDimension {
   constructor(value, valueArrayType, crossfilter, id) {
     this.crossfilter = crossfilter;
-    this.id = id;
+    this._id = id;
 
     // current selection filter, expressed as PostiveIntervals.
     this.currentFilter = [];
@@ -133,11 +133,11 @@ class ScalarDimension {
   }
 
   dispose() {
-    this.crossfilter._freeDimension(this.id);
+    this.crossfilter._freeDimension(this._id);
   }
 
   id() {
-    return this.id;
+    return this._id;
   }
 
   _updateFilters(newFilter) {
@@ -147,26 +147,26 @@ class ScalarDimension {
     // more complex work and just clobber everything.
     //
     if (newFilter.length === 0) {
-      this.crossfilter.selection.deselectAll(this.id);
+      this.crossfilter.selection.deselectAll(this._id);
     } else if (
       newFilter.length === 1 &&
       newFilter[0][0] === 0 &&
       newFilter[0][1] == this.index.length
     ) {
-      this.crossfilter.selection.selectAll(this.id);
+      this.crossfilter.selection.selectAll(this._id);
     } else {
       const adds = PositiveIntervals.difference(newFilter, this.currentFilter);
       const dels = PositiveIntervals.difference(this.currentFilter, newFilter);
       dels.forEach(interval =>
         this.crossfilter.selection.deselectIndirectFromRange(
-          this.id,
+          this._id,
           this.index,
           interval
         )
       );
       adds.forEach(interval =>
         this.crossfilter.selection.selectIndirectFromRange(
-          this.id,
+          this._id,
           this.index,
           interval
         )