Handle boolean values (#360)

* Handle false literals in interpolations.

* Add another test for explicit false

* Check for true

* Remove typeof value === 'boolean' since value does not exist

packages/emotion/src/index.js

@@ -120,7 +120,7 @@ function handleInterpolation(
   if (
     interpolation === undefined ||
     interpolation === null ||
-    typeof value === 'boolean'
+    typeof interpolation === 'boolean'
   ) {
     return ''
   }

packages/emotion/test/__snapshots__/css.test.js.snap

@@ -12,6 +12,32 @@ exports[`css @supports 1`] = `
 />
 `;
 
+exports[`css array with explicit false 1`] = `
+.glamor-0 {
+  display: -webkit-box;
+  display: -webkit-flex;
+  display: -ms-flexbox;
+  display: flex;
+}
+
+<div
+  className="glamor-0"
+/>
+`;
+
+exports[`css array with explicit true 1`] = `
+.glamor-0 {
+  display: -webkit-box;
+  display: -webkit-flex;
+  display: -ms-flexbox;
+  display: flex;
+}
+
+<div
+  className="glamor-0"
+/>
+`;
+
 exports[`css auto px 1`] = `
 .glamor-0 {
   display: -webkit-box;
@@ -160,6 +186,12 @@ exports[`css explicit & 2`] = `
 }"
 `;
 
+exports[`css explicit false 1`] = `
+<div
+  className="css-0"
+/>
+`;
+
 exports[`css falsy property value in object 1`] = `
 .glamor-0 {
   display: -webkit-box;

packages/emotion/test/css.test.js

@@ -168,6 +168,25 @@ describe('css', () => {
     const tree = renderer.create(<div className={cls1} />).toJSON()
     expect(tree).toMatchSnapshot()
   })
+
+  test('explicit false', () => {
+    const cls1 = css(false)
+    const tree = renderer.create(<div className={cls1} />).toJSON()
+    expect(tree).toMatchSnapshot()
+  })
+
+  test('array with explicit false', () => {
+    const cls1 = css([[{ display: 'flex' }], false])
+    const tree = renderer.create(<div className={cls1} />).toJSON()
+    expect(tree).toMatchSnapshot()
+  })
+
+  test('array with explicit true', () => {
+    const cls1 = css([[{ display: 'flex' }], true])
+    const tree = renderer.create(<div className={cls1} />).toJSON()
+    expect(tree).toMatchSnapshot()
+  })
+
   test('nested', () => {
     const cls1 = css`
       color: yellow;