md-wechat/src/assets/scripts/uploadImageFile.js

import fileApi from "../../api/file";

export function uploadImgFile(file) {
    return new Promise((resolve, reject) => {
        const checkImageResult = isImageIllegal(file);
        if (checkImageResult) {
            reject(checkImageResult);
            return;
        }

        const base64Reader = new FileReader();
        base64Reader.readAsDataURL(file);
        base64Reader.onload = function () {
            const base64Content = this.result.split(",").pop();
            fileApi
                .fileUpload(base64Content, file)
                .then((res) => {
                    resolve(res);
                })
                .catch((err) => {
                    reject(err);
                });
        };
    });
}

export function isImageIllegal(file) {
    if (!/\.(gif|jpg|jpeg|png|GIF|JPG|PNG)$/.test(file.name)) {
        return "请上传 JPG/PNG/GIF 格式的图片";
    }
    if (file.size > 5 * 1024 * 1024) {
        return "由于公众号限制，图片大小不能超过 5.0M";
    }
    return false;
}