代码语言：javascript
复制if (typeof Object.assign != 'function') {
Object.assign = function (target) {
'use strict';
if (target == null) {
throw new TypeError('Cannot convert undefined or null to object');
}
target = Object(target);
for (var index = 1; index < arguments.length; index ) {
var source = arguments[index];
if (source != null) {
for (var key in source) {
if (Object.prototype.hasOwnProperty.call(source, key)) {
target[key] = source[key];
}
}
}
}
return target;
};
}
代码语言：javascript
复制if (typeof String.prototype.startsWith != 'function') {
String.prototype.startsWith = function (str) {
if (str == null || str == '' || this.length == 0 || str.length > this.length)
return false;
return this.substr(0, str.length) == str;
};
}
if (typeof String.prototype.endsWith != 'function') {
String.prototype.endsWith = function (str) {
if (str == null || str == '' || this.length == 0 || str.length > this.length)
return false;
return this.substring(this.length - str.length) == str;
};
}
