Function warnOnce

src/utils.js:93–101

(message)

let warned = {};

export function warnOnce(message) {
  if (!warned[message]) {
    /* istanbul ignore else */
    if (typeof console !== 'undefined') {
      console.error(message); // eslint-disable-line no-console
    }
    warned[message] = true;
  }
}

export function deprecated(propType, explanation) {
  return function validate(props, propName, componentName, ...rest) {