js中三目运算符和&& || 符的个人浅见

$(".lgn").on("click", function() {
        var a = {};
        a.loginType = $(this).data("logintype");
        a.loginType == wx_utils.LOGIN_TYPE.WX ? (a.username = $("#username").val(), a.password = $("#password").val()) : a.loginType == wx_utils.LOGIN_TYPE.ECARD && (a.username = f || $("#username_").val(), a.password = $("#password_").val(), a.customerCode = d || $("#customerCode").val(), a.outid = $("#outid").val());
        a.scopes = [];
        $("input[name='scope_box']:checked").each(function(b, c) {
            a.scopes.push(c.value)
        });
        wx_utils.login(a, !1, function(a) {
            a && 202102 == a.errorCode ? ($(".modal-overlay").addClass("modal-overlay-visible"), $("#bind_ecard_div").show()) : wx_utils.toast(a)
        })
    });

var c = 1;
c==1 ? console.log(c),console.log('1') : console.log('c不等于1');

var a = 5;
function abc() {
    console.log('我是方法abc')
}
function err() {
    console.log('我是方法err')
}

a==2 ? (abc()):err();
a==5 ? (abc(),abc()):err();

var  n = 0;
if(n >= 10){
n =0;
}else{
n ++;
}
console.log(n);
n = 1;

var m = 0;
m = m >= 10 ? m=0 : m++;
console.log(m);
m = 0;

var  n = 0;
if(n >= 10){
n =0;
}else{
++n;
}
console.log(n);
n = 1;

var m = 0;
m = m >= 10 ? m=0 : ++m;
console.log(m);
m = 1;

//if else 实现
var add_level = 0; 
if(add_step == 5){ 
  add_level = 1; 
}else if(add_step == 10){ 
  add_level = 2; 
}else if(add_step == 12){ 
  add_level = 3; 
}else if(add_step == 15){ 
  add_level = 4; 
}else { 
  add_level = 0; 
}

//也可以用switch实现
var add_level = 0; 
switch(add_step){ 
  case 5 : 
    add_level = 1; 
    break; 
  case 10 : 
    add_level = 2; 
      break; 
  case 12 : 
     add_level = 3; 
    break; 
  case 15 :
    add_level = 4; 
    break; 
  default : 
    add_level = 0; 
    break;
}

//&& ||实现
var add_level = (add_step==5 && 1) || (add_step==10 && 2) || (add_step==12 && 3) || (add_step==15 && 4) || 0; 

//更优雅的方式
var add_level={'5':1,'10':2,'12':3,'15':4}[add_step] || 0; 
//此方法还看不太懂，希望前辈看到给我分析下。

var add_level = (add_step>12 && 4) || (add_step>10 && 3) || (add_step>5 && 2) || (add_step>0 && 1) || 0; 

typeof 5
"number"
typeof !!5
"boolean"

<div ng-include="user.admin&&'edit.admin.html'||'edit.user.html'">
</div>

var attr = true && 4 && “aaa”;
结果是attr = aaa

var attr = attr || “”;

if(a >=5){ 
  alert("你好"); 
} 
//可以改写成
a >= 5 && alert("你好"); 

var Yahoo = Yahoo || {};

var wrap = 
    // option or optgroup 
    !tags.indexOf("<opt") && 
    [ 1, "<select multiple='multiple'>", "</select>" ] || 

    !tags.indexOf("<leg") && 
    [ 1, "<fieldset>", "</fieldset>" ] || 

    tags.match(/^<(thead|tbody|tfoot|colg|cap)/) && 
    [ 1, "<table>", "</table>" ] || 

    !tags.indexOf("<tr") && 
    [ 2, "<table><tbody>", "</tbody></table>" ] || 

    // <thead> matched above 
    (!tags.indexOf("<td") || !tags.indexOf("<th")) && 
    [ 3, "<table><tbody><tr>", "</tr></tbody></table>" ] || 

    !tags.indexOf("<col") && 
    [ 2, "<table><tbody></tbody><colgroup>", "</colgroup></table>" ] || 

    // IE can't serialize <link> and <script> tags normally 
    !jQuery.support.htmlSerialize && 
    [ 1, "div<div>", "</div>" ] || 

    [ 0, "", "" ]; 

    // Go to html and back, then peel off extra wrappers 
    div.innerHTML = wrap[1] + elem + wrap[2]; 

    // Move to the right depth 
    while ( wrap[0]-- ) 
        div = div.lastChild;