@material-ui/core/es/styles/createSpacing.js

React components that implement Google's Material Design.

import warning from 'warning';
let warnOnce;
export default function createSpacing(spacingInput = 8) {
  // Already transformed.
  if (spacingInput.mui) {
    return spacingInput;
  } // All components align to an 8dp square baseline grid for mobile, tablet, and desktop.
  // https://material.io/design/layout/understanding-layout.html#pixel-density


  let transform;

  if (typeof spacingInput === 'function') {
    transform = spacingInput;
  } else {
    process.env.NODE_ENV !== "production" ? warning(typeof spacingInput === 'number', [`Material-UI: the \`theme.spacing\` value (${spacingInput}) is invalid.`, 'It should be a number or a function.'].join('\n')) : void 0;

    transform = factor => {
      process.env.NODE_ENV !== "production" ? warning(typeof factor === 'number', `Expected spacing argument to be a number, got ${factor}`) : void 0;
      return spacingInput * factor;
    };
  }

  const spacing = (...args) => {
    process.env.NODE_ENV !== "production" ? warning(args.length <= 4, `Material-UI: Too many arguments provided, expected between 0 and 4, got ${args.length}`) : void 0;

    if (args.length === 0) {
      return transform(1);
    }

    if (args.length === 1) {
      return transform(args[0]);
    }

    return args.map(factor => {
      const output = transform(factor);
      return typeof output === 'number' ? `${output}px` : output;
    }).join(' ');
  }; // Backward compatibility, to remove in v5.


  Object.defineProperty(spacing, 'unit', {
    get: () => {
      if (process.env.NODE_ENV !== 'production') {
        process.env.NODE_ENV !== "production" ? warning(warnOnce && process.env.NODE_ENV !== 'test', ['Material-UI: theme.spacing.unit usage has been deprecated.', 'It will be removed in v5.', 'You can replace `theme.spacing.unit * y` with `theme.spacing(y)`.', '', 'You can use the `https://github.com/mui-org/material-ui/tree/master/packages/material-ui-codemod/README.md#theme-spacing-api` migration helper to make the process smoother.'].join('\n')) : void 0;
        warnOnce = true;
      }

      return spacingInput;
    }
  });
  spacing.mui = true;
  return spacing;
}