for of 迭代可迭代对象
function count(str) { const m = {} for(let k of str){ if(k === ' ') continue if(k in m){ m[k]++ } else { m[k] = 1 } } return m }
for of 迭代可迭代对象
function count(str) { const m = {} for(let k of str){ if(k === ' ') continue if(k in m){ m[k]++ } else { m[k] = 1 } } return m }