fine-tuning of toNumber function (#4684)
fine-tuning of toNumber function (#4684)

1. parseFloat() support only one param, see MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseFloat
2. maybe it's better to use isNaN() to judge the conversion result?
Kingwl/vue,Ddder-FE/vue,Ddder-FE/vue,vuejs/vue,lizhiyao/vue,KingMario/vue,KingMario/vue,leemotive/vue,xueyaodeai/vue,vuejs/vue,optimizely/vue,greennyreborn/vue,Kingwl/vue,lizhiyao/vue,Hanks10100/vue,xueyaodeai/vue,Ddder-FE/vue,leemotive/vue,Jinjiang/vue,greennyreborn/vue,vuejs/vue,lizhiyao/vue,cnchanning/vue,KingMario/vue,leemotive/vue,Kingwl/vue,Ddder-FE/vue,vuejs/vue,xueyaodeai/vue,Hanks10100/vue,Jinjiang/vue,xueyaodeai/vue,greennyreborn/vue,KingMario/vue,leemotive/vue,Jinjiang/vue,Kingwl/vue,Hanks10100/vue,cnchanning/vue,Jinjiang/vue,Hanks10100/vue,lizhiyao/vue,greennyreborn/vue,cnchanning/vue