checker.js

	export default {
	isNumber : function (checkVal){
		var reg = /^-?[1-9][0-9]?.?[0-9]*$/;
		return reg.test(checkVal);
	},
	    /**
	     * @description 小数点前后位数限制
		 * “当前输入的值”、“小数点前限制的位数”、“小数点后限制的位数”
	     */
	 limitByPoint: function(val, limitBeforePoint, limitAfterPoint) {
	   const pointNum = (val.includes(".") && val.match(/\./g).length) || 0; // 小数点数量
	   let limitValue = '0';
	   if (pointNum === 0) {
	     // 不包含小数点
	      // 移除开头的0，除非值只有一位且是0
	         val = val.replace(/^0+/, (m) => (m.length === val.length && m.length === 1 ? m : ''));
	         // 如果值仍然为0且长度大于1位，则设置为空字符串（或根据需要设置默认值）
	         if (val === '0' && val.length > 1) {
	           val = '';
	         }
	     if (val.length > limitBeforePoint) {
	       limitValue = val.substring(0, limitBeforePoint);
	     } else {
	       limitValue = val;
	     }
	   } else if (pointNum === 1) {
	     // 小数点数量为1
	     const pointIndex = val.indexOf("."); // 小数点所在位置的索引
	     const valueBeforePoint = val.substring(0, pointIndex); // 小数点前的数
	     const valueAfterPoint = val.substring(pointIndex + 1); // 小数点后的数
	     // 限制小数点前的位数
	     if (valueBeforePoint.length > limitBeforePoint) {
			 console.log(valueBeforePoint.substring(0, limitBeforePoint),valueAfterPoint)
	       limitValue = valueBeforePoint.substring(0, limitBeforePoint) + "." + valueAfterPoint;
			uni.showToast({
			  title: "请输入正确的值,小数点前的数值位数最大为"+limitBeforePoint+"位",
			  icon: "none",
			});
		 }
	 
	     // 限制小数点后的位数
	     if (valueAfterPoint.length > limitAfterPoint) {
	       limitValue = valueBeforePoint + "." + valueAfterPoint.substring(0, limitAfterPoint);
			uni.showToast({
			  title: "请输入正确的值,小数点位数只能保留"+limitAfterPoint+"位",
			  icon: "none",
			});
		 } else {
	       limitValue = val; // 如果没有超出小数点后的限制，则保持原值
	     }
	   } else {
	     // 小点数量大于1，属于错误值
	     uni.showToast({
	       title: "请输入正确的值",
	       icon: "none",
	     });
	     limitValue = ''; // 清空值或设置为默认值
	   }
	 
	   return limitValue;
	 }
}

在页面引用

<template>
<form>
<view class="uni-form-item">
				<view class="mb10px color-6a6a6a">核销借款</view>
				<input type="number" placeholder="请输入核销借款" v-model="form.unitPrice" @input="limitByPoint($event,'unitPrice',8,3)" />
			</view>
</form>
</template>
<script>
	import checker from "@/utils/checker.js"
	export default {
		data() {
			return {
			form: {
					id: null,
					unitPrice:0
				}
			}
		},
		methods: {
			// “当前输入的值”、“key名称”、“小数点前限制的位数”、“小数点后限制的位数”，
			limitByPoint(event, formVal,beforNum,afterNum) {
				let val = graceChecker.limitByPoint(event.detail.value, beforNum, afterNum)
				this.$nextTick(() => {
				  this.form[formVal]=val
				})
			}
		}
}
</script>