warning源码

warning(condition,format) condition为否值时报错，从第三个参数开始字符串替换format中的"%s"

 

'use strict';

var emptyFunction = require('./emptyFunction');

// condition为否值，format中%s转化为剩余参数，通过console.error打印错误文本或直接报错
var warning = emptyFunction;

if (process.env.NODE_ENV !== 'production') {
  (function () {
    var printWarning = function printWarning(format) {
      for (var _len = arguments.length, args = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
        args[_key - 1] = arguments[_key];
      }

      var argIndex = 0;
      var message = 'Warning: ' + format.replace(/%s/g, function () {
        return args[argIndex++];
      });
      if (typeof console !== 'undefined') {
        console.error(message);
      }
      try {
        throw new Error(message);
      } catch (x) {}
    };

    warning = function warning(condition, format) {
      if (format === undefined) {
        throw new Error('`warning(condition, format, ...args)` requires a warning ' + 'message argument');
      }

      if (format.indexOf('Failed Composite propType: ') === 0) {
        return;
      }

      if (!condition) {
        for (var _len2 = arguments.length, args = Array(_len2 > 2 ? _len2 - 2 : 0), _key2 = 2; _key2 < _len2; _key2++) {
          args[_key2 - 2] = arguments[_key2];
        }

        printWarning.apply(undefined, [format].concat(args));
      }
    };
  })();
}

module.exports = warning;