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Ivan Starkov istarkov

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istarkov / serialize.js
Last active Sep 10, 2019
Serialize promise calls (run promises sequentially)
View serialize.js
// promise
const sleep = (timeout, v) => new Promise(r => setTimeout(() => r(v), timeout));
// series to call
const series = [() => sleep(1000, 1), () => sleep(1000, 2), () => sleep(1000, 3)];
// serialize
const r = series
.reduce(
(m, p) => m.then(v => Promise.all([...v, p()])),
Promise.resolve([])
View 01-howto-setup-nginx-with-http2-on-ubuntu-12-04.md

The problem: old ubuntu does not support chrome http2 as chrome uses APLN which is exists in openssl ^1.0.2h

create file /etc/apt/sources.list.d/nginx.list and add lines

deb http://nginx.org/packages/mainline/ubuntu/ trusty nginx
deb-src http://nginx.org/packages/mainline/ubuntu/ trusty nginx
View question.md

I want to hold ordering of some items in SQL, like field in a table index: 0,1,2,3,4,... and I have operation moveItem

If I want to move item from index: 1 to index: 3 I can do

delete from table where index = 1;
update table set index = index - 1 where index > 1
update table set index = index + 1 where index >=3
insert into table (index) values (3)
@istarkov
istarkov / 00 README.md
Last active Nov 26, 2017
How to style React components
View 00 README.md

How to style React components

If you use sass and css-modules and want to restyle some base component without changing its code. (base component already use css-modules and exposes styles property)

I know two way how to do it.

  1. Using composes css-modules operator. Just extend classes you need, then in javascript code combine both styles as {...baseStyle, ...myStyleSimple}
View classBasedEnhancer.js
/* @flow */
import * as React from 'react'
import { compose, withProps } from 'recompose'
import type { HOC } from 'recompose'
// Example of very dirty written fetcher enhancer
function fetcher<Response: {}, Base: {}>(
dest: string,
nullRespType: ?Response
): HOC<{ ...$Exact<Base>, data?: Response }, Base> {
return BaseComponent =>
View simpleTypedEnhancer.js
/* @flow */
import * as React from 'react'
import { compose, withProps } from 'recompose'
import type { HOC } from 'recompose'
function mapProps<BaseProps: {}, EnhancedProps>(
mapperFn: EnhancedProps => BaseProps
): (React.ComponentType<BaseProps>) => React.ComponentType<EnhancedProps> {
return Component => props => <Component {...mapperFn(props)} />
}
View UseHocBase.js
type MyComponentProps = HOCBase<typeof myEnhancer>
class MyComponent extends React.Component<MyComponentProps> {
render() ...
}
const MyEnhancedComponent = myEnhancer(MyComponent)
View HOCBase.js
// Extract type from any enhancer
type HOCBase_<A, B, C: HOC<A, B>> = A
type HOCBase<C> = HOCBase_<*, *, C>
View enhancedBase.js
/* @flow */
import React from 'react'
import { compose, defaultProps, withProps } from 'recompose'
import type { HOC } from 'recompose';
// type of Enhanced component props
type EnhancedComponentProps = {
text?: string,
};
View withProps.js
// change output type of withProps
// from `HOC<A & B, B>` to `HOC<{ ...$Exact<B>, ...A }, B>`
type EnhancedCompProps = { b: number }
const enhancer2: HOC<*, EnhancedCompProps> = compose(
withProps(({ b }) => ({
b: `${b}`,
})),
withProps(({ b }) => ({
// $ExpectError The operand of an arithmetic operation must be a number