如果是数组，我将使用indexof来防止重复。
但我认为indexof不能防止对象中的重复。
我使用reduce找到了这段代码。 这可能是一个解决方案，但不知道如何采用。
list.reduce((acc, current) => {
const x = acc.find(item => item.name === current.name);
if (!x) {
return acc.concat([current]);
} else {
return acc;
}
}, []);
return list;
有什么帮助吗？
null
var list = [];
var data = {
name : '',
id : '',
bDate : '',
iDate : '',
absent : [{
reason : '',
start: '',
end : ''
}]
}
function addBasicInfo(dataName, id, birthday, movein){
var data = {
name : dataName,
id : id,
bDate : birthday,
iDate : movein,
absent : [{
reason : '',
start: '',
end : ''
}]
}
if(list.length === 0){
console.log("[alert] Register the member data for the first time.");
list.splice(0, 1);
list.push(data);
console.log(list);
return list;
} else if (list.length > 0) {
console.log("[alert] More than one member data has been registered on the roll book.")
for(var i = 0; i < list.length; i++){
if(list[i].name == dataName){
console.log("[alert] The member name has been already declared. Put the number after the name to identify namesakes.");
return console.log(list);
} else if(list[i].name !== dataName){
console.log("[alert] Register new member data. ");
list.push(data);
console.log(list);
return list;
}
}
}
}
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01'); // line no. 27-32
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01'); // line no. 34 & 35-37 (prevented to be put in an object)
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01'); // line no. 34 & 39-43
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01'); // line no. 34 & 39-43. (it's supposed to be line no. 35-37) (not prevented to be put in an object)null
您可以使用array.find
null
var list = [];
var data = {
name : '',
id : '',
bDate : '',
iDate : '',
absent : [{
reason : '',
start: '',
end : ''
}]
}
function addBasicInfo(dataName, id, birthday, movein){
var data = {
name : dataName,
id : id,
bDate : birthday,
iDate : movein,
absent : [{
reason : '',
start: '',
end : ''
}]
}
// check for duplicates
if (list.find(item => item.name === dataName)) return console.log("an item with this name already exists");
if(list.length === 0){
console.log("[alert] Register the member data for the first time.");
list.splice(0, 1);
list.push(data);
console.log(list);
return list;
} else if (list.length > 0) {
console.log("[alert] More than one member data has been registered on the roll book.")
for(var i = 0; i < list.length; i++){
if(list[i].name == dataName){
console.log("[alert] The member name has been already declared. Put the number after the name to identify namesakes.");
return console.log(list);
} else if(list[i].name !== dataName){
console.log("[alert] Register new member data. ");
list.push(data);
console.log(list);
return list;
}
}
}
}
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01'); // line no. 27-32
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01'); // line no. 34 & 35-37 (prevented to be put in an object)
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01'); // line no. 34 & 39-43
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01'); // line no. 34 & 39-43. (it's supposed to be line no. 35-37) (not prevented to be put in an object)
这可以简化
null
var list = [];
function addBasicInfo(dataName, id, birthday, movein){
let item = list.find(pr => pr.dataName === dataName);
if(!item) {
item = {
name : dataName,
id : id,
bDate : birthday,
iDate : movein,
absent : [{
reason : '',
start: '',
end : ''
}]
}
list = [...list, item]
return;
}
item = {
...item,
name : dataName,
id : id,
bDate : birthday,
iDate : movein
}
list = [...list.filter(pr => pr.dataName !== dataName), item]
}
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01'); // line no. 27-32
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01'); // line no. 34 & 35-37 (prevented to be put in an object)
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01'); // line no. 34 & 39-43
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01'); // line no. 34 & 39-43. (it's supposed to be line no. 35-37) (not prevented to be put in an object)
console.log(list)
下面是一个可能的解决方案:
null
var list = [];
function addBasicInfo(name, id, birthday, movein){
var data = {
name : name,
id : id,
bDate : birthday,
iDate : movein,
absent : [{
reason : '',
start: '',
end : ''
}]
}
if(list.length === 0){
console.log("[alert] Register the member data for the first time.");
} else {
console.log("[alert] More than one member data has been registered on the roll book.")
}
var sameMember = list.find(function(m) { return m.name === name });
if (sameMember) {
console.log("[alert] The member name has been already declared. Put the number after the name to identify namesakes.");
} else {
console.log("[alert] Register new member data. ");
list.push(data);
}
return list;
}
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01');
addBasicInfo('Jack','Singer','1974-03-15','1993-12-01');
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01');
addBasicInfo('Nick','Teacher','1980-01-01','1999-05-01');
console.log(list);