我需要var x必须只是一个数字而不是文本。
我怎么能在条件下写这个？*
答案 0 :(得分：1)
if (variable.isNaN()) { // it's a string
} else { // It's a number
}
答案 1 :(得分：0)
有很多替代方法，但最简单的方法如下：
第一个解决方案：
使用整数作为变量Feed const voteAction = (framework) => {
return {
type: "VOTE",
payload: framework
}
}
const updateCurrentPercentages = (voteState) => {
return {
type: "UPDATE_CURRENT_PERCENTAGES",
payload: voteState
}
}
export const castVote = (framework) => (dispatch, getState) => {
dispatch(voteAction(framework));
dispatch(updateCurrentPercentages(getState().votes)); //this does pass in current vote state correctly
}
如果你export function currentPercentageReducer(state=intitialPercentages, action){
switch (action.type){
case "UPDATE_CURRENT_PERCENTAGES":
let totalVotes = action.payload.angular + action.payload.react + action.payload.vue;
//totalVotes, and individual percentage calculations are
//all console.logged correctly.
//EX. if there is one vote for each of the three frameworks
//I get totalVotes = 3, pctAngular = 1/3, pctReact = 1/3,
//pctVue = 1/3
console.log('totalVotes', totalVotes)
console.log('pctAngular', action.payload.angular + ' / ' + totalVotes);
console.log('pctReact', action.payload.react + ' / ' + totalVotes);
console.log('pctVue', action.payload.vue + ' / ' + totalVotes);
let pctAngular = Math.floor(action.payload.angular / totalVotes) * 100;
let pctReact = Math.floor(action.payload.react / totalVotes) * 100;
let pctVue = Math.floor(action.payload.vue / totalVotes) * 100;
//as soon as I vote for two or more different options
//the console.log below always returns 0,0,0
console.log(pctAngular, pctReact, pctVue);
//returns the correct state when you only vote for one
//option, but when you vote for two or more returns
// {angular:0, react:0, vue:0}
return Object.assign({}, state, {
angular: pctAngular,
react: pctReact,
vue: pctVue
});
default:
return state
}
}
，你会看到结果是12（整数），而不是字符串
第2个解决方案：
只需使用var x = 12;
EXP：
console.log(x)结果与上面的结果相同
如果你需要检查变量是一个数字：
parseInt()如果您需要字符串变量中的提取编号，请进行一些搜索。 问候