[system] Fix handling of null-ish values (mui#24527)

oliviertassinari · web-flow · commit 569c72e8d3ea · 2021-01-21T15:05:44.000+01:00
diff --git a/packages/material-ui-system/src/spacing.js b/packages/material-ui-system/src/spacing.js
@@ -123,7 +123,7 @@ export function createUnarySpacing(theme) {
 }
 
 function getValue(transformer, propValue) {
-  if (typeof propValue === 'string') {
+  if (typeof propValue === 'string' || propValue == null) {
     return propValue;
   }
 
diff --git a/packages/material-ui-system/src/spacing.test.js b/packages/material-ui-system/src/spacing.test.js
@@ -171,4 +171,15 @@ describe('spacing', () => {
       paddingTop: '10px',
     });
   });
+
+  it('should allow to conditionally set a value', () => {
+    const foo = true;
+    const output = spacing({
+      theme: {},
+      pt: foo ? undefined : 2,
+    });
+    expect(output).to.deep.equal({
+      paddingTop: undefined,
+    });
+  });
 });

Original file line number	Diff line number	Diff line change
`@@ -123,7 +123,7 @@ export function createUnarySpacing(theme) {`
`123`	`123`	`}`
`124`	`124`
`125`	`125`	`function getValue(transformer, propValue) {`
`126`		`- if (typeof propValue === 'string') {`
	`126`	`+ if (typeof propValue === 'string' \|\| propValue == null) {`
`127`	`127`	`return propValue;`
`128`	`128`	`}`
`129`	`129`