uniapp 临时图片路径转为base64

/**
 * 临时图片路径转base64
 * @param {Object} param 传一个对象,对象里包括
 * url: 临时图片存放路径,图片路径是相对路径
 * type: 图片类型,如:png
 */
export function base64Image(url, type) {
    return new Promise((resolve, reject) => {
        if (!!uni.getFileSystemManager()) {
            uni.getFileSystemManager().readFile({
                filePath: url, // 图片路径是相对路径
                encoding: "base64", // 编码格式
                success: (res) => {
                    resolve("data:image/" + type.toLocaleLowerCase() + ";base64," + res.data);
                },
                fail: (error) => {
					reject(error.errMsg)
				},
            });
        } else {
            uni.request({
                url: url,
                method: "GET",
                responseType: "arraybuffer",
                success: (res) => {
                    let base64 = wx.arrayBufferToBase64(res.data); // 把arraybuffer转成base64
                    base64 = "data:image/jpeg;base64," + base64; // 不加上这串字符,在页面无法显示
                    resolve(base64);
                },
                fail: (error) => {
					reject(error.errMsg)
				},
            });
        }
    });
}