[英]How to check a Javascript array that contains at least one value that starts with a particular text (eg. ROLE_)
我有下面的javascript“下划線”代碼,用於檢查給定的USER_ROLES是否至少有一個VALID_ROLES。 如果是,則返回true,否則返回false。 工作正常。
但是我想對其進行重構,以便刪除硬編碼角色VALID_ROLES,並檢查是否至少有一個以ROLE_開頭的角色。 如何做呢 ?
// Function to check if least one valid role is present
var USER_ROLES = ['ROLE_5'];
function hasAnyRole(USER_ROLES) {
var VALID_ROLES = [ 'ROLE_1', 'ROLE_2', 'ROLE_3', 'ROLE_4' ];
for (var i = 0; i < USER_ROLES.length; i++) {
if (_.contains(VALID_ROLES, USER_ROLES[i])) {
console.log("Found a valid role, returning true.");
return true;
}
}
console.log("No valid role found, returning false.");
return false;
}
您已經很接近了,但是對於您想要的內容,不需要使用下划線:
for (var i = 0; i < USER_ROLES.length; i++) {
if (typeof USER_ROLES[i].indexOf == "function" && USER_ROLES[i].indexOf("ROLE_") > -1) {
console.log("Found a valid role, returning true.");
//return true;
}
}
用這個。 不需要下划線,您可以使用.some數組
USER_ROLES.some(function(value){
return value.substring(0, 5) === "ROLE_";
});
var index, value, result;
for (index = 0; index < USER_ROLES.length; ++index) {
value = USER_ROLES[index];
if (value.substring(0, 5) === "ROLE_") {
// You've found it, the full text is in `value`.
// So you might grab it and break the loop, although
// really what you do having found it depends on
// what you need.
result = value;
break;
}
}
// Use `result` here, it will be `undefined` if not found
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