1. module koa-cors
   1. function koa-cors (options)

module koa-cors

function koa-cors (options)

• description and source-code

  function getMiddleware(options) {
  
    options = options || {};
  
    var defaults = {
      origin: true,
      methods: 'GET,HEAD,PUT,POST,DELETE'
    };
  
    // Set defaults
    for (var key in defaults) {
      if (!options.hasOwnProperty(key)) {
        options[key] = defaults[key];
      }
    }
  
    // Set expose
    if (Array.isArray(options.expose)) {
      options.expose = options.expose.join(',');
    }
  
    // Set maxAge
    if (typeof options.maxAge === 'number') {
      options.maxAge = options.maxAge.toString();
    } else {
      options.maxAge = null;
    }
  
    // Set methods
    if (Array.isArray(options.methods)) {
      options.methods = options.methods.join(',');
    }
  
    // Set headers
    if (Array.isArray(options.headers)) {
      options.headers = options.headers.join(',');
    }
  
    return function* cors(next) {
  
      /**
       * Access Control Allow Origin
       */
      var origin;
  
      if (typeof options.origin === 'string') {
        origin = options.origin;
      } else if (options.origin === true) {
        origin = this.get('origin') || '*';
      } else if (options.origin === false) {
        origin = options.origin;
      } else if (typeof options.origin === 'function') {
        origin = options.origin(this.request);
      }
  
      if (origin === false) return;
  
      this.set('Access-Control-Allow-Origin', origin);
  
      /**
       * Access Control Expose Headers
       */
      if (options.expose) {
        this.set('Access-Control-Expose-Headers', options.expose);
      }
  
      /**
       * Access Control Max Age
       */
      if (options.maxAge) {
        this.set('Access-Control-Max-Age', options.maxAge);
      }
  
      /**
       * Access Control Allow Credentials
       */
      if (options.credentials === true) {
        this.set('Access-Control-Allow-Credentials', 'true');
      }
  
      /**
       * Access Control Allow Methods
       */
      this.set('Access-Control-Allow-Methods', options.methods);
  
      /**
       * Access Control Allow Headers
       */
      var headers;
  
      if (options.headers) {
        headers = options.headers;
      } else {
        headers = this.get('access-control-request-headers');
      }
  
      if (headers) {
        this.set('Access-Control-Allow-Headers', headers);
      }
  
      /**
       * Returns
       */
      if (this.method === 'OPTIONS') {
        this.status = 204;
      } else {
        yield next;
      }
    };
  }

• example usage

  n/a