Deprecate many library api's, unify others

lib/Error.js

@@ -1,29 +1,15 @@
 'use strict';
 
-const utils = require('./utils');
-
 /**
  * StripeError is the base error from which all other more specific Stripe errors derive.
  * Specifically for errors returned from Stripe's REST API.
  */
 class StripeError extends Error {
   constructor(raw = {}) {
     super(raw.message);
-    // This splat is here for back-compat and should be removed in the next major version.
-    this.populate(...arguments);
     this.type = this.constructor.name;
-  }
 
-  /**
-   * DEPRECATED
-   * This will be inlined in the constructor in the future.
-   */
-  populate(raw) {
     this.raw = raw;
-    if (!raw || typeof raw !== 'object') {
-      return;
-    }
-
     this.rawType = raw.type;
     this.code = raw.code;
     this.param = raw.param;
@@ -60,21 +46,6 @@ class StripeError extends Error {
         return new GenericError('Generic', 'Unknown Error');
     }
   }
-
-  /**
-   * DEPRECATED
-   * Please use class inheritance instead.
-   */
-  static extend(options) {
-    const type = options.type;
-    class CustomError extends StripeError {}
-    Object.defineProperty(CustomError, 'name', {
-      value: type,
-    });
-    delete options.type;
-    Object.assign(CustomError.prototype, options);
-    return CustomError;
-  }
 }
 
 // Specific Stripe Error types:
@@ -145,28 +116,6 @@ class StripeIdempotencyError extends StripeError {}
  */
 class StripeInvalidGrantError extends StripeError {}
 
-/**
- * DEPRECATED
- * This is here for backwards compatibility and will be removed in the next major version.
- */
-function _Error(raw) {
-  this.populate(...arguments);
-  this.stack = new Error(this.message).stack;
-}
-_Error.prototype = Object.create(Error.prototype);
-_Error.prototype.type = 'GenericError';
-_Error.prototype.populate = function(type, message) {
-  this.type = type;
-  this.message = message;
-};
-_Error.extend = utils.protoExtend;
-
-/**
- * DEPRECATED.
- * Do not use the default export; it may be removed or change in a future version.
- */
-module.exports = _Error;
-
 module.exports.StripeError = StripeError;
 module.exports.StripeCardError = StripeCardError;
 module.exports.StripeInvalidRequestError = StripeInvalidRequestError;