Add validity check for integers (observablehq#348)

* Add isValidInteger checks

* Update tests

Author: mkfreeman

src/table.js

@@ -517,6 +517,7 @@ function descendingDefined(a, b) {
 
 // Functions for checking type validity
 const isValidNumber = (value) => typeof value === "number" && !Number.isNaN(value);
+const isValidInteger = (value) => Number.isInteger(value) && !Number.isNaN(value);
 const isValidString = (value) => typeof value === "string";
 const isValidBoolean = (value) => typeof value === "boolean";
 const isValidBigint = (value) => typeof value === "bigint";
@@ -537,6 +538,8 @@ export function getTypeValidator(colType) {
       return isValidBoolean;
     case "number":
       return isValidNumber;
+    case "integer":
+      return isValidInteger;
     case "date":
       return isValidDate;
     case "buffer":

test/table-test.js

@@ -825,7 +825,8 @@ describe("getTypeValidator filters accurately", () => {
     {label: "buffer", value: new ArrayBuffer()},
     {label: "boolean", value: true},
     {label: "array", value: [1, 2, 3]},
-    {label: "number", value: 10},
+    {label: "number", value: 10.1},
+    {label: "integer", value: 10},
     {label: "date", value: new Date(1)},
     // eslint-disable-next-line no-undef
     {label: "bigint", value: BigInt(10)},
@@ -846,7 +847,15 @@ describe("getTypeValidator filters accurately", () => {
 
   it("filters numbers", () => {
     const isValid = getTypeValidator("number");
-    assert.deepStrictEqual(source.filter(d => isValid(d.value)), [{label: "number", value: 10}]);
+    assert.deepStrictEqual(source.filter(d => isValid(d.value)), [{label: "number", value: 10.1}, {label: "integer", value: 10}]);
+  });
+
+  it("filters integers", () => {
+    const isValid = getTypeValidator("integer");
+    assert.deepStrictEqual(
+      source.filter((d) => isValid(d.value)),
+      [{label: "integer", value: 10}]
+    );
   });
 
   it("filters booleans", () => {
@@ -890,7 +899,8 @@ describe("getTypeValidator filters accurately", () => {
       {label: "buffer", value: new ArrayBuffer()},
       {label: "boolean", value: true},
       {label: "array", value: [1, 2, 3]},
-      {label: "number", value: 10},
+      {label: "number", value: 10.1},
+      {label: "integer", value: 10},
       {label: "date", value: new Date(1)},
       // eslint-disable-next-line no-undef
       {label: "bigint", value: BigInt(10)},