react-native 引入纯javascript

今天下午，不会做react-native引入javascript，不是类类型的，而是纯的javascript,会了其实很简单，不会就完了

一个普通的javascript（CSA.js），完了之后把需要导出的函数或者变量以 export{ AA,BB}导出

然后在引入的地方  Import  { AA} from ‘./CSA’;即可  使用的地方 alert(AA);

 

例如

引入地方

import { base64decode ,base64encodechars } from "./Base64";

使用地方：

alert(base64encodechars);
alert(base64decode('11'));

Base64.js

const base64encodechars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const base64decodechars = new Array(
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
    -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1);


  function   base64encode(str) {
        var out, i, len;
        var c1, c2, c3;
        len = str.length;
        i = 0;
        out = "";
        while (i < len) {
            c1 = str.charCodeAt(i++) & 0xff;
            if (i == len) {
                out += base64encodechars.charAt(c1 >> 2);
                out += base64encodechars.charAt((c1 & 0x3) << 4);
                out += "==";
                break;
            }
            c2 = str.charCodeAt(i++);
            if (i == len) {
                out += base64encodechars.charAt(c1 >> 2);
                out += base64encodechars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4));
                out += base64encodechars.charAt((c2 & 0xf) << 2);
                out += "=";
                break;
            }
            c3 = str.charCodeAt(i++);
            out += base64encodechars.charAt(c1 >> 2);
            out += base64encodechars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4));
            out += base64encodechars.charAt(((c2 & 0xf) << 2) | ((c3 & 0xc0) >> 6));
            out += base64encodechars.charAt(c3 & 0x3f);
        }
        return out;
    }

    function base64decode(str) {
        var c1, c2, c3, c4;
        var i, len, out;

        len = str.length;

        i = 0;
        out = "";
        while (i < len) {

            do {
                c1 = base64decodechars[str.charCodeAt(i++) & 0xff];
            } while (i < len && c1 == -1);
            if (c1 == -1)
                break;

            do {
                c2 = base64decodechars[str.charCodeAt(i++) & 0xff];
            } while (i < len && c2 == -1);
            if (c2 == -1)
                break;

            out += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

            do {
                c3 = str.charCodeAt(i++) & 0xff;
                if (c3 == 61)
                    return out;
                c3 = base64decodechars[c3];
            } while (i < len && c3 == -1);
            if (c3 == -1)
                break;

            out += String.fromCharCode(((c2 & 0xf) << 4) | ((c3 & 0x3c) >> 2));

            do {
                c4 = str.charCodeAt(i++) & 0xff;
                if (c4 == 61)
                    return out;
                c4 = base64decodechars[c4];
            } while (i < len && c4 == -1);
            if (c4 == -1)
                break;
            out += String.fromCharCode(((c3 & 0x03) << 6) | c4);
        }
        return out;
    }

export { base64decode ,base64encode} //导出
export { base64encodechars }  //导出