Replace second use of requests module

The deprecated requests module was also being used in
`base#makeRequests` even though it was no longer in the list of
installed packages in package.json browserify was pulling it it which
was the root cause of the package being so bloated (because I was
not longer replaceing requests with xhr).

This replaces `request` with `node-fetch` in `makeRequest`.
`makeRequest`s isn't not actually used anywhere. All API calls actually
are going through `runAction` instead and I think maybe `makeRequest`s
should just be removed but in order to do that we need to get more
clarity around what is public vs private.

lib/base.js

@@ -4,10 +4,10 @@ var forEach = require('lodash/forEach');
 var get = require('lodash/get');
 var assign = require('lodash/assign');
 var isPlainObject = require('lodash/isPlainObject');
+var fetch = require('node-fetch');
+var AbortController = require('abort-controller');
 
-// This will become require('xhr') in the browser.
-var request = require('request');
-
+var objectToQueryParamString = require('./object_to_query_param_string');
 var AirtableError = require('./airtable_error');
 var Table = require('./table');
 var HttpHeaders = require('./http_headers');
@@ -34,59 +34,76 @@ Base.prototype.makeRequest = function(options) {
 
     var method = get(options, 'method', 'GET').toUpperCase();
 
+    var url =
+        this._airtable._endpointUrl +
+        '/v' +
+        this._airtable._apiVersionMajor +
+        '/' +
+        this._id +
+        get(options, 'path', '/') +
+        '?' +
+        objectToQueryParamString(get(options, 'qs', {}));
+
+    var controller = new AbortController();
+
     var requestOptions = {
         method: method,
-        url:
-            this._airtable._endpointUrl +
-            '/v' +
-            this._airtable._apiVersionMajor +
-            '/' +
-            this._id +
-            get(options, 'path', '/'),
-        qs: get(options, 'qs', {}),
         headers: this._getRequestHeaders(get(options, 'headers', {})),
-        json: true,
-        timeout: this._airtable.requestTimeout,
+        signal: controller.signal,
     };
+
     if ('body' in options && _canRequestMethodIncludeBody(method)) {
-        requestOptions.body = options.body;
+        requestOptions.body = JSON.stringify(options.body);
     }
 
+    var timeout = setTimeout(function() {
+        controller.abort();
+    }, this._airtable.requestTimeout);
+
     return new Promise(function(resolve, reject) {
-        request(requestOptions, function(err, response, body) {
-            if (!err && response.statusCode === 429 && !that._airtable._noRetryIfRateLimited) {
-                var numAttempts = get(options, '_numAttempts', 0);
-                var backoffDelayMs = exponentialBackoffWithJitter(numAttempts);
-                setTimeout(function() {
-                    var newOptions = assign({}, options, {
-                        _numAttempts: numAttempts + 1,
-                    });
-                    that.makeRequest(newOptions)
-                        .then(resolve)
-                        .catch(reject);
-                }, backoffDelayMs);
-                return;
-            }
-
-            if (err) {
+        fetch(url, requestOptions)
+            .then(function(resp) {
+                clearTimeout(timeout);
+                resp.statusCode = resp.status;
+                if (resp.status === 429 && !that._airtable._noRetryIfRateLimited) {
+                    var numAttempts = get(options, '_numAttempts', 0);
+                    var backoffDelayMs = exponentialBackoffWithJitter(numAttempts);
+                    setTimeout(function() {
+                        var newOptions = assign({}, options, {
+                            _numAttempts: numAttempts + 1,
+                        });
+                        that.makeRequest(newOptions)
+                            .then(resolve)
+                            .catch(reject);
+                    }, backoffDelayMs);
+                } else {
+                    resp.json()
+                        .then(function(body) {
+                            var err =
+                                that._checkStatusForError(resp.status, body) ||
+                                _getErrorForNonObjectBody(resp.status, body);
+
+                            if (err) {
+                                reject(err);
+                            } else {
+                                resolve({
+                                    statusCode: resp.status,
+                                    headers: resp.headers,
+                                    body: body,
+                                });
+                            }
+                        })
+                        .catch(function() {
+                            var err = _getErrorForNonObjectBody(resp.status);
+                            reject(err);
+                        });
+                }
+            })
+            .catch(function(err) {
+                clearTimeout(timeout);
                 err = new AirtableError('CONNECTION_ERROR', err.message, null);
-            } else {
-                err =
-                    that._checkStatusForError(response.statusCode, body) ||
-                    _getErrorForNonObjectBody(response.statusCode, body);
-            }
-
-            if (err) {
                 reject(err);
-                return;
-            }
-
-            resolve({
-                statusCode: response.statusCode,
-                headers: response.headers,
-                body: body,
             });
-        });
     });
 };
 
@@ -100,6 +117,7 @@ Base.prototype._getRequestHeaders = function(headers) {
 
     result.set('Authorization', 'Bearer ' + this._airtable._apiKey);
     result.set('User-Agent', userAgent);
+    result.set('Content-Type', 'application/json');
     forEach(headers, function(headerValue, headerKey) {
         result.set(headerKey, headerValue);
     });