1598173080
In this video we will use a code-first approach to building a GraphQL API. This means that the code we write will generate the GraphQL schema as an artifact rather than something we have to maintain ourselves. We’ll be building our own GraphQL resume API in Next.js, Apollo Server, Nexus Schema, and TypeScript. Follow along and try making changes by adding your own data.
#next #apollo #graphql #react
1600347600
This is part 3 of “MS SQL Server- Zero to Hero” and in this article, we will be discussing about the SCHEMAS in SQL SERVER. Before getting into this article, please consider to visit previous articles in this series from below,
In part one, we learned the basics of data, database, database management system, and types of DBMS and SQL.
#sql server #benefits of schemas #create schema in sql #database schemas #how to create schema in sql server #schemas #schemas in sql server #sql server schemas #what is schema in sql server
1598173080
In this video we will use a code-first approach to building a GraphQL API. This means that the code we write will generate the GraphQL schema as an artifact rather than something we have to maintain ourselves. We’ll be building our own GraphQL resume API in Next.js, Apollo Server, Nexus Schema, and TypeScript. Follow along and try making changes by adding your own data.
#next #apollo #graphql #react
1632537859
Not babashka. Node.js babashka!?
Ad-hoc CLJS scripting on Node.js.
Experimental. Please report issues here.
Nbb's main goal is to make it easy to get started with ad hoc CLJS scripting on Node.js.
Additional goals and features are:
Nbb requires Node.js v12 or newer.
CLJS code is evaluated through SCI, the same interpreter that powers babashka. Because SCI works with advanced compilation, the bundle size, especially when combined with other dependencies, is smaller than what you get with self-hosted CLJS. That makes startup faster. The trade-off is that execution is less performant and that only a subset of CLJS is available (e.g. no deftype, yet).
Install nbb
from NPM:
$ npm install nbb -g
Omit -g
for a local install.
Try out an expression:
$ nbb -e '(+ 1 2 3)'
6
And then install some other NPM libraries to use in the script. E.g.:
$ npm install csv-parse shelljs zx
Create a script which uses the NPM libraries:
(ns script
(:require ["csv-parse/lib/sync$default" :as csv-parse]
["fs" :as fs]
["path" :as path]
["shelljs$default" :as sh]
["term-size$default" :as term-size]
["zx$default" :as zx]
["zx$fs" :as zxfs]
[nbb.core :refer [*file*]]))
(prn (path/resolve "."))
(prn (term-size))
(println (count (str (fs/readFileSync *file*))))
(prn (sh/ls "."))
(prn (csv-parse "foo,bar"))
(prn (zxfs/existsSync *file*))
(zx/$ #js ["ls"])
Call the script:
$ nbb script.cljs
"/private/tmp/test-script"
#js {:columns 216, :rows 47}
510
#js ["node_modules" "package-lock.json" "package.json" "script.cljs"]
#js [#js ["foo" "bar"]]
true
$ ls
node_modules
package-lock.json
package.json
script.cljs
Nbb has first class support for macros: you can define them right inside your .cljs
file, like you are used to from JVM Clojure. Consider the plet
macro to make working with promises more palatable:
(defmacro plet
[bindings & body]
(let [binding-pairs (reverse (partition 2 bindings))
body (cons 'do body)]
(reduce (fn [body [sym expr]]
(let [expr (list '.resolve 'js/Promise expr)]
(list '.then expr (list 'clojure.core/fn (vector sym)
body))))
body
binding-pairs)))
Using this macro we can look async code more like sync code. Consider this puppeteer example:
(-> (.launch puppeteer)
(.then (fn [browser]
(-> (.newPage browser)
(.then (fn [page]
(-> (.goto page "https://clojure.org")
(.then #(.screenshot page #js{:path "screenshot.png"}))
(.catch #(js/console.log %))
(.then #(.close browser)))))))))
Using plet
this becomes:
(plet [browser (.launch puppeteer)
page (.newPage browser)
_ (.goto page "https://clojure.org")
_ (-> (.screenshot page #js{:path "screenshot.png"})
(.catch #(js/console.log %)))]
(.close browser))
See the puppeteer example for the full code.
Since v0.0.36, nbb includes promesa which is a library to deal with promises. The above plet
macro is similar to promesa.core/let
.
$ time nbb -e '(+ 1 2 3)'
6
nbb -e '(+ 1 2 3)' 0.17s user 0.02s system 109% cpu 0.168 total
The baseline startup time for a script is about 170ms seconds on my laptop. When invoked via npx
this adds another 300ms or so, so for faster startup, either use a globally installed nbb
or use $(npm bin)/nbb script.cljs
to bypass npx
.
Nbb does not depend on any NPM dependencies. All NPM libraries loaded by a script are resolved relative to that script. When using the Reagent module, React is resolved in the same way as any other NPM library.
To load .cljs
files from local paths or dependencies, you can use the --classpath
argument. The current dir is added to the classpath automatically. So if there is a file foo/bar.cljs
relative to your current dir, then you can load it via (:require [foo.bar :as fb])
. Note that nbb
uses the same naming conventions for namespaces and directories as other Clojure tools: foo-bar
in the namespace name becomes foo_bar
in the directory name.
To load dependencies from the Clojure ecosystem, you can use the Clojure CLI or babashka to download them and produce a classpath:
$ classpath="$(clojure -A:nbb -Spath -Sdeps '{:aliases {:nbb {:replace-deps {com.github.seancorfield/honeysql {:git/tag "v2.0.0-rc5" :git/sha "01c3a55"}}}}}')"
and then feed it to the --classpath
argument:
$ nbb --classpath "$classpath" -e "(require '[honey.sql :as sql]) (sql/format {:select :foo :from :bar :where [:= :baz 2]})"
["SELECT foo FROM bar WHERE baz = ?" 2]
Currently nbb
only reads from directories, not jar files, so you are encouraged to use git libs. Support for .jar
files will be added later.
The name of the file that is currently being executed is available via nbb.core/*file*
or on the metadata of vars:
(ns foo
(:require [nbb.core :refer [*file*]]))
(prn *file*) ;; "/private/tmp/foo.cljs"
(defn f [])
(prn (:file (meta #'f))) ;; "/private/tmp/foo.cljs"
Nbb includes reagent.core
which will be lazily loaded when required. You can use this together with ink to create a TUI application:
$ npm install ink
ink-demo.cljs
:
(ns ink-demo
(:require ["ink" :refer [render Text]]
[reagent.core :as r]))
(defonce state (r/atom 0))
(doseq [n (range 1 11)]
(js/setTimeout #(swap! state inc) (* n 500)))
(defn hello []
[:> Text {:color "green"} "Hello, world! " @state])
(render (r/as-element [hello]))
Working with callbacks and promises can become tedious. Since nbb v0.0.36 the promesa.core
namespace is included with the let
and do!
macros. An example:
(ns prom
(:require [promesa.core :as p]))
(defn sleep [ms]
(js/Promise.
(fn [resolve _]
(js/setTimeout resolve ms))))
(defn do-stuff
[]
(p/do!
(println "Doing stuff which takes a while")
(sleep 1000)
1))
(p/let [a (do-stuff)
b (inc a)
c (do-stuff)
d (+ b c)]
(prn d))
$ nbb prom.cljs
Doing stuff which takes a while
Doing stuff which takes a while
3
Also see API docs.
Since nbb v0.0.75 applied-science/js-interop is available:
(ns example
(:require [applied-science.js-interop :as j]))
(def o (j/lit {:a 1 :b 2 :c {:d 1}}))
(prn (j/select-keys o [:a :b])) ;; #js {:a 1, :b 2}
(prn (j/get-in o [:c :d])) ;; 1
Most of this library is supported in nbb, except the following:
:syms
.-x
notation. In nbb, you must use keywords.See the example of what is currently supported.
See the examples directory for small examples.
Also check out these projects built with nbb:
See API documentation.
See this gist on how to convert an nbb script or project to shadow-cljs.
Prequisites:
To build:
bb release
Run bb tasks
for more project-related tasks.
Download Details:
Author: borkdude
Download Link: Download The Source Code
Official Website: https://github.com/borkdude/nbb
License: EPL-1.0
#node #javascript
1600219097
GraphQL is a query language and a server-side runtime that is used to request data from the server. The first thing that comes to mind when hearing the term “query language” is SQL. Just as SQL is used for querying databases, GraphQL is a bit like SQL but for querying web APIs as it eliminates the need to repeatedly develop or change existing end-points. GraphQL also enables the client/front-end to retrieve exactly the data they have requested and no more. This means that, within a single request of GraphQL, you can traverse from the entry point to the related data (whereas in RESTful API you have to call multiple endpoints to fetch similar results).
The following example will help you to understand this better. Let us consider an object person which has the attributes name, age, email, and contactNumber. Suppose the front-end only needs the name and age of the person. If we design a REST API, the endpoint will look like api/persons, which will end up fetching all the fields for the person object. The issue arises here because there is no easy way to communicate that I am interested in some fields and not others (which causes REST API to over fetch the data).
#graphql #nodejs #apollo-server #graphql-apollo-server
1598259480
In part two we will build out the frontend of our GraphQL Resume. First we set up the Apollo Client, then fetch and display the data that comes back from our GraphQL API. Lastly we add Prism Code Highlighter to show display the GraphQL query which retrieved the data we are displaying.
#next #apollo #graphql #react