@mui/system/esm/createTheme/createSpacing.js

MUI System is a set of CSS utilities to help you build custom designs more efficiently. It makes it possible to rapidly lay out custom designs.

import { createUnarySpacing } from "../spacing/index.js";

// The different signatures imply different meaning for their arguments that can't be expressed structurally.
// We express the difference with variable names.

export default function createSpacing(spacingInput = 8,
// Material Design layouts are visually balanced. Most measurements align to an 8dp grid, which aligns both spacing and the overall layout.
// Smaller components, such as icons, can align to a 4dp grid.
// https://m2.material.io/design/layout/understanding-layout.html
transform = createUnarySpacing({
  spacing: spacingInput
})) {
  // Already transformed.
  if (spacingInput.mui) {
    return spacingInput;
  }
  const spacing = (...argsInput) => {
    if (process.env.NODE_ENV !== 'production') {
      if (!(argsInput.length <= 4)) {
        console.error(`MUI: Too many arguments provided, expected between 0 and 4, got ${argsInput.length}`);
      }
    }
    const args = argsInput.length === 0 ? [1] : argsInput;
    return args.map(argument => {
      const output = transform(argument);
      return typeof output === 'number' ? `${output}px` : output;
    }).join(' ');
  };
  spacing.mui = true;
  return spacing;
}