js: A repository from ktye

dom

html

<!DOCTYPE html>
<head><meta charset="utf-8"><title></title>
<style>
</style>
</head>
<body onload="init()">
<script>
function init(){}
</script>
</body></html>

general

function ge(x){return document.getElementById(x)}
function ce(x){return document.createElement(x)}
function pd(e){if(e){e.preventDefault();e.stopPropagation()}}
function rm(p){while(p.firstChild)p.removeChild(p.firstChild);return p}
const td_=new TextDecoder("utf-8"),su=x=>td_.decode(x)
const te_=new TextEncoder("utf-8"),us=x=>te_.encode(x)

drop file

window.ondragover=function(e){pd(e)}
window.ondrop=function(e){pd(e);
 let l=e.dataTransfer.files
 for(let i=0;i<l.length;i++){
  let f=l.item(i);
  f.arrayBuffer().then(u=>{
   console.log(f.name,u)
})}}

download

<a id="dl" style="display:none"></a>

let x=new Blob([u],{type:"application/octet-stream"}) //u:uint8array
dl.href=URL.createObjectURL(x)
dl.download="filename.txt"
dl.click()

fetch multiple

function fetchall(l,f){let x=[],F={}
 l.forEach(function(u,i){x.push(fetch(u).then(r=>r.arrayBuffer()).then(r=>F[l[i]]=r))})
 Promise.all(x).then(function(){f(F)})
}

compress

lz4 (uncompress)

function lz(x){let i=7,j,n,t,c,o,r=[],S=-(1<<31),R=(x,a,n)=>{for(j=0;j<n;j++)r.push(x[a+j]);return n},
 h=()=>x[i++]|x[i++]<<8,C=()=>{if(c===15)do{c+=x[i]}while(x[i++]==255)},
 d=(x,n)=>{while(i<n){t=x[i++];c=t>>4;C();i+=R(x,i,c);if(i<n){c=t&15;o=r.length-h();C();R(r,o,4+c)}}}
 while(n=h()|h()<<16)(n&S)?i+=R(x,i,n&~S):d(x,i+n);return new Uint8Array(r)}

u8=compress(u8);u8=uncompress(u8) (snappy)

function compress(u){ //see github.com/zhipeng-jia/snappyjs(0.7.0)
 let G=new Array(15)
 let H=(k,s)=>(k*0x1e35a7bd)>>>s
 let L=(a,p)=>a[p]+(a[p+1]<<8)+(a[p+2]<<16)+(a[p+3]<<24)
 let E=(a,p,q)=>a[p]===a[q]&&a[p+1]===a[q+1]&&a[p+2]===a[q+2]&&a[p+3]===a[q+3]
 let N=function(x,i,n,r,p){
  if(n<=60){r[p]=(n-1)<<2;p++}else if(n<256){r[p]=60<<2;r[p+1]=n-1;p+=2}else{r[p]=61<<2;r[p+1]=(n-1)&255;r[p+2]=(n-1)>>>8;p+=3}
  r.set(x.subarray(i,i+n),p);return p+n}
 let C=function(r,p,o,n){
  if(n<12&&o<2048){r[p]=1+((n-4)<<2)+((o>>>8)<<5);r[p+1]=o&255;return p+2}
  else{r[p]=2+((n-1)<<2);r[p+1]=o&255;r[p+2]=o>>>8;return p+3}}
 let A=function(r,p,o,n){while(n>=68){p=C(r,p,o,64);n-=64}
  if(n>64){p=C(r,p,o,60);n-=60};return C(r,p,o,n)}
 let F=function(x,p,s,r,q){
  let t=1;while((1<<t)<=s&&t<=14)t++;t--
  let h=32-t;if(typeof G[t]==='undefined'){G[t]=new Uint16Array(1<<t)}
  let g=G[t];g.fill(0)
  let e=p+s,l,b=p,n=p,a,d,j,c,k,u,v,m,o,w,y,f=1
  if(s>=15){l=e-15;p++;d=H(L(x,p),h)
   while(f){k=32;j=p
    do{p=j;a=d;u=k>>>5;k++;j=p+u;if(p>l){f=0;break};d=H(L(x,j),h);c=b+g[a];g[a]=p-b}while(!E(x,p,c))
    if(!f)break;q=N(x,n,p-n,r,q)
    do{v=p;m=4;while(p+m<e&&x[p+m]===x[c+m])m++;p+=m;o=v-c;q=A(r,q,o,m);n=p;if(p>=l){f=0;break}
     w=H(L(x,p-1),h);g[w]=p-1-b;y=H(L(x,p),h);c=b+g[y];g[y]=p-b}while(E(x,p,c))
    if(!f)break;p++;d=H(L(x,p),h)
  }};if(n<e)q=N(x,n,e-n,r,q);return q}
 let P=function(v,r,p){do{r[p]=v&127;v=v>>>7;if(v>0)r[p]+=128;p++}while(v>0);return p}
 let M=x=>32+x.length+Math.floor(x.length/6)
 let T=function(r,u){let l=u.length,p=0,n=0,s;n=P(l,r,n);while(p<l){s=Math.min(l-p,1<<16);n=F(u,p,s,r,n);p+=s};return r.slice(0,n)}
 let r=new Uint8Array(M(u));return T(r,u)}
 
 function uncompress(x){ //see github.com/zhipeng-jia/snappyjs(0.7.0) (trusted input)
 let L=function(x){let p=0,r=0,s=0,c,v
  while(s<32&&p<x.length){c=x[p];p++;v=c&127;r|=v<<s;if(c<128)return[r,p];s+=7}}
 let D=function(r,x,p){let n=x.length,q=0,c,l,s,o,W=[0,255,0xffff,0xffffff,0xffffffff]
  while(p<n){c=x[p];p++
   if((c&3)===0){l=(c>>>2)+1
    if(l>60){s=l-60;l=x[p]+(x[p+1]<<8)+(x[p+2]<<16)+(x[p+3]<<24);l=(l&W[s])+1;p+=s}
    r.set(x.subarray(p,p+l),q);p+=l;q+=l
   }else{switch(c&3){
    case 1:l=((c>>>2)&7)+4;o=x[p]+((c>>>5)<<8);p++;break
    case 2:l=(c>>>2)+1;o=x[p]+(x[p+1]<<8);p+=2;break
    case 3:l=(c>>>2)+1;o=x[p]+(x[p+1]<<8)+(x[p+2]<<16)+(x[p+3]<<24);p+=4;break
    default:break}
    for(let i=0;i<l;i++)r[q+i]=r[q+i-o];q+=l}};return r}
 let [n,p]=L(x);return D(new Uint8Array(n),x,p)}

base64

function s64u(u){let c=function(x){let r='';for(let i=0;i<x.length;i++)r+=String.fromCharCode(x[i]);return r};return btoa(c(u))}
function u64s(s){let c=function(x){const r=new Uint8Array(x.length);for(let i=0;i<x.length;i++)r[i]=x.charCodeAt(i);return r};return c(atob(s))}

ktye/js

dom

compress