The following example code about update list item using jQuery Ajax and Axios post method with REST API for your reference.
jQuery Ajax with SharePoint REST API:
<input id="UpdateItem" type="button" value="Update Item" onclick="UpdateListItem()"/>
<script type="text/javascript" src="https://code.jquery.com/jquery-1.12.4.min.js"></script>
<script type="text/javascript">
function UpdateListItem(){
var listName="samplelist";
var itemId=1;
var itemType = GetItemTypeForListName(listName);
var item = {
"__metadata": { "type": itemType },
"Title": "test"
};
$.ajax({
url: _spPageContextInfo.siteAbsoluteUrl + "/_api/web/lists/getbytitle('" + listName + "')/items/getbyid("+itemId+")",
type: "POST",
contentType: "application/json;odata=verbose",
data: JSON.stringify(item),
headers: {
"Accept": "application/json;odata=verbose",
"X-RequestDigest": $("#__REQUESTDIGEST").val(),
"X-HTTP-Method": "MERGE",
"If-Match": "*"
},
success: function (data) {
console.log('Success');
},
error: function (data) {
console.log(JSON.stringify(data));
}
});
}
function GetItemTypeForListName(name) {
return "SP.Data." + name.charAt(0).toUpperCase() + name.split(" ").join("").slice(1) + "ListItem";
}
</script>
axios post with SharePoint REST API:
<input id="UpdateItem" type="button" value="Update Item" onclick="UpdateListItem()"/>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/axios/0.19.0/axios.min.js"></script>
<script type="text/javascript">
function UpdateListItem(){
var listName="samplelist";
var itemId=1;
var url = _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/getbytitle('" + listName+ "')/items/getbyid("+itemId+")";
var configAxios = {
headers: {
"Accept": "application/json;odata=verbose",
"X-RequestDigest": document.getElementById('__REQUESTDIGEST').value,
"X-HTTP-Method": "MERGE",
"If-Match": "*",
"Content-Type":"application/json;odata=verbose"
}
};
var itemType=GetItemTypeForListName(listName);
var data = {
"__metadata": {"type": itemType },
"Title": "MyTest"
};
axios.post(url,data,configAxios).then(function(req){
console.log('Success');
}).catch(function(err){
console.log('error during http call', err);
});
}
function GetItemTypeForListName(name) {
return "SP.Data." + name.charAt(0).toUpperCase() + name.split(" ").join("").slice(1) + "ListItem";
}
</script>