1.1 install express

Author: ShMcK

src/server.js

@@ -0,0 +1,9 @@
+constexpress=require("express");
+
+constapp=express();
+
+constserver=app.listen(process.env.PORT||3000);
+
+// -- DO NOT EDIT BELOW THIS LINE
+
+module.exports=server;

test/dependency.test.js

@@ -0,0 +1,17 @@
+constassert=require("assert");
+
+const{ doesNotThrow, isModuleInstalled }=require("./utils");
+
+describe("package.json",()=>{
+// 1.1.
+it('should have "express" installed',async()=>{
+assert.ok(
+awaitdoesNotThrow(()=>
+isModuleInstalled({
+name: "express",
+type: "dependency"
+})
+)
+);
+});
+});

test/utils.js

@@ -0,0 +1,113 @@
+const{
+promises: { readFile, readdir }
+}=require("fs");
+const{ join }=require("path");
+
+constgetPackageJson=async(dir=process.cwd())=>{
+// load package.json file
+constpathToPackageJson=join(dir,"package.json");
+constpackageJson=awaitreadFile(pathToPackageJson,"utf8").catch(
+console.error
+);
+if(!packageJson){
+thrownewError("Missing root package.json");
+}
+// parse as JSON
+constjson=JSON.parse(packageJson);
+if(!json){
+thrownewError("The package.json content looks invalid");
+}
+returnjson;
+};
+
+exports.getPackageJson=getPackageJson;
+
+constversionMatch=(current,expected)=>{
+letcurrentSemver=current;
+if(["~","^"].includes(current[0])){
+currentSemver=current.substring(1);
+}
+returncurrentSemver===expected;
+};
+
+/**
+ * isModuleInstalled
+ * @param { name, type } params
+ * "name" - the name of the dependency
+ * "type" - "dependency", "devDependency", "peerDependency"
+ * @returns boolean
+ */
+constisModuleInstalled=async({ name, type, version })=>{
+// 1. load package.json file
+constjson=awaitgetPackageJson();
+
+// 2. verify package lists dependency by type
+letinstallCommand;
+lethasDependency;
+letcurrentVersion;
+
+switch(type){
+case"dependency":
+installCommand="--save";
+hasDependency=!!json.dependencies&&json.dependencies[name];
+currentVersion=json.dependencies[name];
+break;
+case"devDependency":
+installCommand="--save-dev";
+hasDependency=!!json.devDependencies&&json.devDependencies[name];
+currentVersion=json.devDependencies[name];
+break;
+case"peerDependency":
+thrownewError("Peer dependencies unsupported");
+default:
+thrownewError("Unsupported packaged type");
+}
+
+if(!hasDependency){
+thrownewError(`Run "npm install ${installCommand}${name}"`);
+}
+
+// 3. if version, check dependency version
+if(version&&!versionMatch(currentVersion,version)){
+thrownewError(
+`Dependency ${name} version ${currentVersion} does not match expected ${version}`
+);
+}
+
+// 4. verify node_module installed
+constpathToNodeModule=join(process.cwd(),"node_modules",name);
+consthasNodeModules=awaitreaddir(pathToNodeModule).catch(()=>{
+thrownewError('Missing node_modules. Run "npm install"');
+});
+if(!hasNodeModules){
+thrownewError('Missing node_modules. Run "npm install"');
+}
+
+// 5. if version, has installed node_module version
+if(version){
+constnodeModulePackageJson=awaitgetPackageJson(pathToNodeModule);
+if(!versionMatch(nodeModulePackageJson.version,version)){
+thrownewError(
+`Dependency ${name} version ${version} is not yet installed. Run "npm install"`
+);
+}
+}
+
+returntrue;
+};
+
+exports.isModuleInstalled=isModuleInstalled;
+
+// created because assert.doesNotThrow not working predictably with async fns
+constdoesNotThrow=asyncfn=>{
+letresult=true;
+try{
+awaitfn();
+}catch(error){
+console.error(error);
+result=false;
+}
+returnresult;
+};
+
+exports.doesNotThrow=doesNotThrow;