前端条件语句,在保持可读性情况下的精简写法?1、正常写法:if (a) { console.log('a');}精简:a && console.log('a');2、正常写法:var a = b;if (!a) { a = 'a';}精简:var a = b || 'a';3、正常写法:if (a) { console.log('a');} else { console.log('b');}精简:a ? console.log('a') : console.log('b');4、正常写法var a;switch (b) { case 'a': a = 'a'; break; case 'b': a = 'b'; break; default: a = 'c';}精简:var a = {a: 'a', b: 'b'}[b] || 'c';