JS基于FileSaver.js插件实现文件保存功能示例
2019年07月21日
本文实例讲述了JS基于FileSaver.js插件实现文件保存功能。分享给大家供大家参考，具体如下：
这里介绍一款js插件用法非常简单，先来看看FileSaver.js插件源码：
/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js */
var saveAs=saveAs||function(e){"use strict";if(typeof navigator!=="undefined"&&/MSIE [1-9]./.test(navigator.userAgent)){return}var t=e.document,n=function(){return e.URL||e.webkitURL||e},r=t.createElementNS("http://www.w3.org/1999/xhtml","a"),i="download"in r,o=function(e){var t=new MouseEvent("click");e.dispatchEvent(t)},a=/Version/[d.]+.*Safari/.test(navigator.userAgent),f=e.webkitRequestFileSystem,u=e.requestFileSystem||f||e.mozRequestFileSystem,s=function(t){(e.setImmediate||e.setTimeout)(function(){throw t},0)},c="application/octet-stream",d=0,l=500,w=function(t){var r=function(){if(typeof t==="string"){n().revokeObjectURL(t)}else{t.remove()}};if(e.chrome){r()}else{setTimeout(r,l)}},p=function(e,t,n){t=[].concat(t);var r=t.length;while(r--){var i=e["on"+t[r]];if(typeof i==="function"){try{i.call(e,n||e)}catch(o){s(o)}}}},v=function(e){if(/^s*(?:text/S*|application/xml|S*/S*+xml)s*;.*charsets*=s*utf-8/i.test(e.type)){return new Blob(["ufeff",e],{type:e.type})}return e},y=function(t,s,l){if(!l){t=v(t)}var y=this,m=t.type,S=false,h,R,O=function(){p(y,"writestart progress write writeend".split(" "))},g=function(){if(R&&a&&typeof FileReader!=="undefined"){var r=new FileReader;r.onloadend=function(){var e=r.result;R.location.href="data:attachment/file"+e.slice(e.search(/[,;]/));y.readyState=y.DONE;O()};r.readAsDataURL(t);y.readyState=y.INIT;return}if(S||!h){h=n().createObjectURL(t)}if(R){R.location.href=h}else{var i=e.open(h,"_blank");if(i==undefined&&a){e.location.href=h}}y.readyState=y.DONE;O();w(h)},b=function(e){return function(){if(y.readyState!==y.DONE){return e.apply(this,arguments)}}},E={create:true,exclusive:false},N;y.readyState=y.INIT;if(!s){s="download"}if(i){h=n().createObjectURL(t);r.href=h;r.download=s;setTimeout(function(){o(r);O();w(h);y.readyState=y.DONE});return}if(e.chrome&&m&&m!==c){N=t.slice||t.webkitSlice;t=N.call(t,0,t.size,c);S=true}if(f&&s!=="download"){s+=".download"}if(m===c||f){R=e}if(!u){g();return}d+=t.size;u(e.TEMPORARY,d,b(function(e){e.root.getDirectory("saved",E,b(function(e){var n=function(){e.getFile(s,E,b(function(e){e.createWriter(b(function(n){n.onwriteend=function(t){R.location.href=e.toURL();y.readyState=y.DONE;p(y,"writeend",t);w(e)};n.onerror=function(){var e=n.error;if(e.code!==e.ABORT_ERR){g()}};"writestart progress write abort".split(" ").forEach(function(e){n["on"+e]=y["on"+e]});n.write(t);y.abort=function(){n.abort();y.readyState=y.DONE};y.readyState=y.WRITING}),g)}),g)};e.getFile(s,{create:false},b(function(e){e.remove();n()}),b(function(e){if(e.code===e.NOT_FOUND_ERR){n()}else{g()}}))}),g)}),g)},m=y.prototype,S=function(e,t,n){return new y(e,t,n)};if(typeof navigator!=="undefined"&&navigator.msSaveOrOpenBlob){return function(e,t,n){if(!n){e=v(e)}return navigator.msSaveOrOpenBlob(e,t||"download")}}m.abort=function(){var e=this;e.readyState=e.DONE;p(e,"abort")};m.readyState=m.INIT=0;m.WRITING=1;m.DONE=2;m.error=m.onwritestart=m.onprogress=m.onwrite=m.onabort=m.onerror=m.onwriteend=null;return S}(typeof self!=="undefined"&&self||typeof window!=="undefined"&&window||this.content);if(typeof module!=="undefined"&&module.exports){module.exports.saveAs=saveAs}else if(typeof define!=="undefined"&&define!==null&&define.amd!=null){define([],function(){return saveAs})}
源码可读性不敢恭维，让我们用本站的JS在线工具：http://tools.laike.net/code/js 格式化一下，方便以后阅读研究。
格式化后的代码如下：
/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/FileSaver.js */
var saveAs = saveAs ||
function(e) {
"use strict";
if (typeof navigator !== "undefined" && /MSIE [1-9]./.test(navigator.userAgent)) {
return
}
var t = e.document,
n = function() {
return e.URL || e.webkitURL || e
},
r = t.createElementNS("http://www.w3.org/1999/xhtml", "a"),
i = "download" in r,
o = function(e) {
var t = new MouseEvent("click");
e.dispatchEvent(t)
},
a = /Version/[d.]+.*Safari/.test(navigator.userAgent),
f = e.webkitRequestFileSystem,
u = e.requestFileSystem || f || e.mozRequestFileSystem,
s = function(t) { (e.setImmediate || e.setTimeout)(function() {
throw t
},
0)
},
c = "application/octet-stream",
d = 0,
l = 500,
w = function(t) {
var r = function() {
if (typeof t === "string") {
n().revokeObjectURL(t)
} else {
t.remove()
}
};
if (e.chrome) {
r()
} else {
setTimeout(r, l)
}
},
p = function(e, t, n) {
t = [].concat(t);
var r = t.length;
while (r--) {
var i = e["on" + t[r]];
if (typeof i === "function") {
try {
i.call(e, n || e)
} catch(o) {
s(o)
}
}
}
},
v = function(e) {
if (/^s*(?:text/S*|application/xml|S*/S*+xml)s*;.*charsets*=s*utf-8/i.test(e.type)) {
return new Blob(["ufeff", e], {
type: e.type
})
}
return e
},
y = function(t, s, l) {
if (!l) {
t = v(t)
}
var y = this,
m = t.type,
S = false,
h, R, O = function() {
p(y, "writestart progress write writeend".split(" "))
},
g = function() {
if (R && a && typeof FileReader !== "undefined") {
var r = new FileReader;
r.onloadend = function() {
var e = r.result;
R.location.href = "data:attachment/file" + e.slice(e.search(/[,;]/));
y.readyState = y.DONE;
O()
};
r.readAsDataURL(t);
y.readyState = y.INIT;
return
}
if (S || !h) {
h = n().createObjectURL(t)
}
if (R) {
R.location.href = h
} else {
var i = e.open(h, "_blank");
if (i == undefined && a) {
e.location.href = h
}
}
y.readyState = y.DONE;
O();
w(h)
},
b = function(e) {
return function() {
if (y.readyState !== y.DONE) {
return e.apply(this, arguments)
}
}
},
E = {
create: true,
exclusive: false
},
N;
y.readyState = y.INIT;
if (!s) {
s = "download"
}
if (i) {
h = n().createObjectURL(t);
r.href = h;
r.download = s;
setTimeout(function() {
o(r);
O();
w(h);
y.readyState = y.DONE
});
return
}
if (e.chrome && m && m !== c) {
N = t.slice || t.webkitSlice;
t = N.call(t, 0, t.size, c);
S = true
}
if (f && s !== "download") {
s += ".download"
}
if (m === c || f) {
R = e
}
if (!u) {
g();
return
}
d += t.size;
u(e.TEMPORARY, d, b(function(e) {
e.root.getDirectory("saved", E, b(function(e) {
var n = function() {
e.getFile(s, E, b(function(e) {
e.createWriter(b(function(n) {
n.onwriteend = function(t) {
R.location.href = e.toURL();
y.readyState = y.DONE;
p(y, "writeend", t);
w(e)
};
n.onerror = function() {
var e = n.error;
if (e.code !== e.ABORT_ERR) {
g()
}
};
"writestart progress write abort".split(" ").forEach(function(e) {
n["on" + e] = y["on" + e]
});
n.write(t);
y.abort = function() {
n.abort();
y.readyState = y.DONE
};
y.readyState = y.WRITING
}), g)
}), g)
};
e.getFile(s, {
create: false
},
b(function(e) {
e.remove();
n()
}), b(function(e) {
if (e.code === e.NOT_FOUND_ERR) {
n()
} else {
g()
}
}))
}), g)
}), g)
},
m = y.prototype,
S = function(e, t, n) {
return new y(e, t, n)
};
if (typeof navigator !== "undefined" && navigator.msSaveOrOpenBlob) {
return function(e, t, n) {
if (!n) {
e = v(e)
}
return navigator.msSaveOrOpenBlob(e, t || "download")
}
}
m.abort = function() {
var e = this;
e.readyState = e.DONE;
p(e, "abort")
};
m.readyState = m.INIT = 0;
m.WRITING = 1;
m.DONE = 2;
m.error = m.onwritestart = m.onprogress = m.onwrite = m.onabort = m.onerror = m.onwriteend = null;
return S
} (typeof self !== "undefined" && self || typeof window !== "undefined" && window || this.content);
if (typeof module !== "undefined" && module.exports) {
module.exports.saveAs = saveAs
} else if (typeof define !== "undefined" && define !== null && define.amd != null) {
define([],
function() {
return saveAs
})
}
使用的时候非常简单，代码如下所示：
var blob = new Blob(['out_put_string'], {type: "text/plain;charset=utf-8"});//out_put_string为需要保存到文件的字符串内容
saveAs(blob, "filename.php");//filename.php为保存的文件名
PS：本站在线工具《PHP代码在线格式化美化工具》中的保存文本功能使用的就是FileSaver.js插件实现的。感兴趣的朋友可以参考一下：
http://tools.laike.net/code/phpformat
更多关于JavaScript相关内容感兴趣的读者可查看本站专题：《JavaScript扩展技巧总结》、《JavaScript文件与目录操作技巧汇总》、《JavaScript错误与调试技巧总结》、《JavaScript数据结构与算法技巧总结》、《JavaScript遍历算法与技巧总结》及《JavaScript数学运算用法总结》
希望本文所述对大家JavaScript程序设计有所帮助。
