fix(@inquirer/number): Allowing decimal numbers (#1485)

Due to javascript floating point arithmetic the current code does not support decimal numbers as input. However, by multiplying by with 10^6 this now works as intended.

---------

Co-authored-by: Simon Boudrias <admin@simonboudrias.com>

packages/number/number.test.mts

@@ -350,4 +350,20 @@ describe('number prompt', () => {
 
     expect(getScreen()).toMatchInlineSnapshot(`"Q: Answer must be: 2 === _2_"`);
   });
+
+  it('handle decimal steps', async () => {
+    const { answer, events, getScreen } = await render(number, {
+      message: 'Enter a decimal number',
+      min: 1,
+      max: 100,
+      step: 0.01,
+    });
+
+    expect(getScreen()).toMatchInlineSnapshot(`"? Enter a decimal number"`);
+
+    events.type('10.01');
+    events.keypress('enter');
+    await expect(answer).resolves.toEqual(10.01);
+    expect(getScreen()).toMatchInlineSnapshot(`"? Enter a decimal number 10.01"`);
+  });
 });

packages/number/src/index.mts

@@ -21,6 +21,14 @@ type NumberConfig = {
   theme?: PartialDeep<Theme>;
 };
 
+function isStepOf(value: number, step: number, min: number): boolean {
+  const valuePow = value * Math.pow(10, 6);
+  const stepPow = step * Math.pow(10, 6);
+  const minPow = min * Math.pow(10, 6);
+
+  return (valuePow - (Number.isFinite(min) ? minPow : 0)) % stepPow === 0;
+}
+
 function validateNumber(
   value: number | undefined,
   {
@@ -37,7 +45,7 @@ function validateNumber(
     return false;
   } else if (value < min || value > max) {
     return `Value must be between ${min} and ${max}`;
-  } else if (step !== 'any' && (value - (Number.isFinite(min) ? min : 0)) % step !== 0) {
+  } else if (step !== 'any' && !isStepOf(value, step, min)) {
     return `Value must be a multiple of ${step}${Number.isFinite(min) ? ` starting from ${min}` : ''}`;
   }