use lodash instead of underscore

package.json

@@ -9,13 +9,15 @@
     "expect.js": "^0.3.1",
     "express": "^4.16.3",
     "json3": "^3.3.2",
+    "lodash.omit": "^4.5.0",
+    "lodash.omitby": "^4.6.0",
+    "lodash.partial": "^4.2.1",
     "mocha": "^5.2.0",
     "morgan": "^1.9.0",
     "q": "^1.5.1",
     "request": "^2.88.0",
     "serverless-http": "^1.6.0",
-    "sinon": "^4.5.0",
-    "underscore": "^1.9.1"
+    "sinon": "^4.5.0"
   },
   "devDependencies": {
     "blanket": "^1.1.7",

server/cloudflare.js

@@ -1,10 +1,10 @@
 'use strict';
 
-const u = require('underscore');
+const omitBy = require('lodash.omitby');
 
 // remove all CloudFlare headers, since they block requests that are already proxied (through the jsonp.afeld.me)
 module.exports.filterHeaders = function(headers) {
-  return u.omit(headers, function(val, header) {
+  return omitBy(headers, function(val, header) {
     return /^cf-/.test(header);
   });
 };

server/proxy-request.js

@@ -1,12 +1,12 @@
 'use strict';
 
 const requestp = require('./requestp');
-const u = require('underscore');
+const omit = require('lodash.omit');
 const cloudflare = require('./cloudflare');
 
 let passThroughHeaders = function(incomingHeaders) {
   // remove those that node should generate
-  let externalReqHeaders = u.omit(
+  let externalReqHeaders = omit(
     incomingHeaders,
     'accept-encoding',
     'connection',

server/router.js

@@ -1,7 +1,8 @@
 'use strict';
 
 const express = require('express');
-const u = require('underscore');
+const omit = require('lodash.omit');
+const partial = require('lodash.partial');
 const JSON3 = require('json3');
 const snippets = require('./snippets');
 const proxy = require('./proxy-request');
@@ -22,7 +23,7 @@ let serveLandingPage = function(req, res) {
 
 let passBackHeaders = function(incomingHeaders) {
   // remove those that node should generate
-  let resultHeaders = u.omit(
+  let resultHeaders = omit(
     incomingHeaders,
     'connection',
     'content-length',
@@ -71,7 +72,7 @@ let doProxy = function(apiUrl, req, res) {
       // keep this right before respond() to handle errors from any previous steps
       errorToJson
     )
-    .then(u.partial(respond, res))
+    .then(partial(respond, res))
     .done();
 };