flow like the river

VISUALIZACION/node_modules/polished/lib/mixins/between.js.flow

@@ -0,0 +1,64 @@
+// @flow
+import getValueAndUnit from '../helpers/getValueAndUnit'
+import PolishedError from '../internalHelpers/_errors'
+
+/**
+ * Returns a CSS calc formula for linear interpolation of a property between two values. Accepts optional minScreen (defaults to '320px') and maxScreen (defaults to '1200px').
+ *
+ * @example
+ * // Styles as object usage
+ * const styles = {
+ *   fontSize: between('20px', '100px', '400px', '1000px'),
+ *   fontSize: between('20px', '100px')
+ * }
+ *
+ * // styled-components usage
+ * const div = styled.div`
+ *   fontSize: ${between('20px', '100px', '400px', '1000px')};
+ *   fontSize: ${between('20px', '100px')}
+ * `
+ *
+ * // CSS as JS Output
+ *
+ * h1: {
+ *   'fontSize': 'calc(-33.33333333333334px + 13.333333333333334vw)',
+ *   'fontSize': 'calc(-9.090909090909093px + 9.090909090909092vw)'
+ * }
+ */
+export default function between(
+  fromSize: string | number,
+  toSize: string | number,
+  minScreen?: string = '320px',
+  maxScreen?: string = '1200px',
+): string {
+  const [unitlessFromSize, fromSizeUnit] = getValueAndUnit(fromSize)
+  const [unitlessToSize, toSizeUnit] = getValueAndUnit(toSize)
+  const [unitlessMinScreen, minScreenUnit] = getValueAndUnit(minScreen)
+  const [unitlessMaxScreen, maxScreenUnit] = getValueAndUnit(maxScreen)
+
+  if (
+    typeof unitlessMinScreen !== 'number'
+    || typeof unitlessMaxScreen !== 'number'
+    || !minScreenUnit
+    || !maxScreenUnit
+    || minScreenUnit !== maxScreenUnit
+  ) {
+    throw new PolishedError(47)
+  }
+
+  if (
+    typeof unitlessFromSize !== 'number'
+    || typeof unitlessToSize !== 'number'
+    || fromSizeUnit !== toSizeUnit
+  ) {
+    throw new PolishedError(48)
+  }
+
+  if (fromSizeUnit !== minScreenUnit || toSizeUnit !== maxScreenUnit) {
+    throw new PolishedError(76)
+  }
+
+  const slope = (unitlessFromSize - unitlessToSize) / (unitlessMinScreen - unitlessMaxScreen)
+  const base = unitlessToSize - slope * unitlessMaxScreen
+  return `calc(${base.toFixed(2)}${fromSizeUnit || ''} + ${(100 * slope).toFixed(2)}vw)`
+}