我试图在全局helpers.js文件中公开我的一些函数，这样我就可以直接调用它们而无需导入它们。这是我的javascript文件：
function icon_string(num, white){
return "https://flyhomes.imgix.net/icons/icons_" + (white ? "w" : "b") +"_v2-" + num.toString() + ".svg";
}
Number.prototype.format = function(decPlaces, thouSeparator, decSeparator) {
var n = this,
decPlaces = isNaN(decPlaces = Math.abs(decPlaces)) ? 2 : decPlaces,
decSeparator = decSeparator == undefined ? "." : decSeparator,
thouSeparator = thouSeparator == undefined ? "," : thouSeparator,
sign = n < 0 ? "-" : "",
i = parseInt(n = Math.abs(+n || 0).toFixed(decPlaces)) + "",
j = (j = i.length) > 3 ? j % 3 : 0;
return sign + (j ? i.substr(0, j) + thouSeparator : "") + i.substr(j).replace(/(\d{3})(?=\d)/g, "$1" + thouSeparator) + (decPlaces ? decSeparator + Math.abs(n - i).toFixed(decPlaces).slice(2) : "");
};
Array.prototype.clean = function(deleteValue) {
for (var i = 0; i < this.length; i++) {
if (this[i] == deleteValue) {
this.splice(i, 1);
i--;
}
}
return this;
};
Array.prototype.move = function (old_index, new_index) {
if (new_index >= this.length) {
var k = new_index - this.length;
while ((k--) + 1) {
this.push(undefined);
}
}
this.splice(new_index, 0, this.splice(old_index, 1)[0]);
return this; // for testing purposes
};
function setCookie(cname, cvalue, exdays) {
var d = new Date();
d.setTime(d.getTime() + (exdays*24*60*60*1000));
var expires = "expires="+d.toUTCString();
document.cookie = cname + "=" + cvalue + "; " + expires;
}
function getCookie(cname) {
var name = cname + "=";
var ca = document.cookie.split(';');
for(var i=0; i<ca.length; i++) {
var c = ca[i];
while (c.charAt(0)==' ') c = c.substring(1);
if (c.indexOf(name) == 0) return c.substring(name.length, c.length);
}
return "";
}
String.prototype.replaceAll = function(search, replacement) {
var target = this;
return target.replace(new RegExp(search, 'g'), replacement);
};
function containsObjectID(obj, list) {
var i;
for (i = 0; i < list.length; i++) {
if (list[i].id === obj.id) {
return true;
}
}
return false;
}
function containsObjectIndex(obj, list) {
var i;
for (i = 0; i < list.length; i++) {
if (list[i].id === obj.id) {
return i;
}
}
return -1;
}
function getParameterByName(name) {
var match = RegExp('[?&]' + name + '=([^&]*)').exec(window.location.search);
return match && decodeURIComponent(match[1].replace(/\+/g, ' '));
}
function updateQueryStringParameter(uri, key, value) {
var re = new RegExp("([?&])" + key + "=.*?(&|$)", "i");
var separator = uri.indexOf('?') !== -1 ? "&" : "?";
if (uri.match(re)) {
return uri.replace(re, '$1' + key + "=" + value + '$2');
}
else {
return uri + separator + key + "=" + value;
}
}
function removeQueryStringParameter(url, parameter) {
var urlparts= url.split('?');
if (urlparts.length>=2) {
var prefix= encodeURIComponent(parameter)+'=';
var pars= urlparts[1].split(/[&;]/g);
for (var i= pars.length; i-- > 0;) {
if (pars[i].lastIndexOf(prefix, 0) !== -1) {
pars.splice(i, 1);
}
}
url= urlparts[0]+'?'+pars.join('&');
return url;
} else {
return url;
}
}
function paramsToObject(params){
var query_string = {};
var query = params;
var vars = query.split("&");
for (var i=0;i<vars.length;i++) {
var pair = vars[i].split("=");
// If first entry with this name
if (typeof query_string[pair[0]] === "undefined") {
query_string[pair[0]] = decodeURIComponent(pair[1]);
// If second entry with this name
} else if (typeof query_string[pair[0]] === "string") {
var arr = [ query_string[pair[0]],decodeURIComponent(pair[1]) ];
query_string[pair[0]] = arr;
// If third or later entry with this name
} else {
query_string[pair[0]].push(decodeURIComponent(pair[1]));
}
}
return query_string;
}
function humanize(str) {
var frags = str.split('_');
frags[0] = frags[0].charAt(0).toUpperCase() + frags[0].slice(1);
return frags.join(' ');
}
String.prototype.capitalize = function() {
return this.charAt(0).toUpperCase() + this.slice(1);
}
// Warn if overriding existing method
if(Array.prototype.equals)
console.warn("Overriding existing Array.prototype.equals. Possible causes: New API defines the method, there's a framework conflict or you've got double inclusions in your code.");
// attach the .equals method to Array's prototype to call it on any array
Array.prototype.equals = function (array) {
// if the other array is a falsy value, return
if (!array)
return false;
// compare lengths - can save a lot of time
if (this.length != array.length)
return false;
for (var i = 0, l=this.length; i < l; i++) {
// Check if we have nested arrays
if (this[i] instanceof Array && array[i] instanceof Array) {
// recurse into the nested arrays
if (!this[i].equals(array[i]))
return false;
}
else if (this[i] != array[i]) {
// Warning - two different object instances will never be equal: {x:20} != {x:20}
return false;
}
}
return true;
}
// Hide method from for-in loops
Object.defineProperty(Array.prototype, "equals", {enumerable: false});
exports.onMobile = function() {
var check = false;
(function(a){if(/(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino/i.test(a)||/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(a.substr(0,4))) check = true;})(navigator.userAgent||navigator.vendor||window.opera);
return check;
};
很抱歉添加整个文件，但我想提请注意一些应用于基类本身的函数（例如Number，String等），而其他函数则按原样声明。
为了公开它们，我尝试在webpack.config.js中添加别名，如下所示：
module.exports = {
...
resolve: {
extensions: ['.json', '.jsx', '.js'],
alias: {
'helpers': path.resolve(__dirname, './vendor/assets/javascripts/helpers.js')
}
},
plugins: [
new webpack.ProvidePlugin({
helpers: 'helpers'
})
],
...
};
但是，由于我持怀疑态度，它并没有奏效。当我们需要一个特定的全局库并且我们有它的javascript文件时，我从实例中复制了这个想法，我们遵循上述方法。但显然，这与导入特定文件有关，而不是包含此类功能的文件，并且一次全局导出它们。你可以通过webpack或我哪里出错来帮助我如何做到这一点？
答案 0 :(得分：1)
该别名只保存helpers.js文件的位置值。 在其他文件中引用它只是意味着别名被替换为帮助文件 String 和而不是其内容。
我还要非常仔细地考虑不使用辅助函数污染全局范围。如果有的话你可以使用一个命名空间变量来保存你的函数作为名称空间的方法。想想lodash的'_'或更简单的vanilla JS Math对象。
<强> BTW: Augmenting or extending the native JavaScript object is highly discouraged