Angular 6 - Get all changed values on FormGroup
I'm new with Angular and I'm wondering if we can get all the values that has changed and only those one.
For example,
this.form = this.formBuilder.group({
name: '',
age: '',
city: ''
});
In my html template, I would like to have 3 inputs, one for each formcontrol of my form. I also want to have a button, when I click on it, the resulting action should be sending to my backend only the changed values (PATCH method).
I don't see how we can do this. I've tried with the observable 'valueChanges', but it returns the whole form and I don't see how it can help me.
Any idea ?
Thanks !
angular asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
add a comment |
I'm new with Angular and I'm wondering if we can get all the values that has changed and only those one.
For example,
this.form = this.formBuilder.group({
name: '',
age: '',
city: ''
});
In my html template, I would like to have 3 inputs, one for each formcontrol of my form. I also want to have a button, when I click on it, the resulting action should be sending to my backend only the changed values (PATCH method).
I don't see how we can do this. I've tried with the observable 'valueChanges', but it returns the whole form and I don't see how it can help me.
Any idea ?
Thanks !
angular asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
Take a snapshot of the form when you populate it first. Compare with that snapshot before submitting.
– JB Nizet
Nov 22 '18 at 23:56
add a comment |
I'm new with Angular and I'm wondering if we can get all the values that has changed and only those one.
For example,
this.form = this.formBuilder.group({
name: '',
age: '',
city: ''
});
In my html template, I would like to have 3 inputs, one for each formcontrol of my form. I also want to have a button, when I click on it, the resulting action should be sending to my backend only the changed values (PATCH method).
I don't see how we can do this. I've tried with the observable 'valueChanges', but it returns the whole form and I don't see how it can help me.
Any idea ?
Thanks !
angular asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
I'm new with Angular and I'm wondering if we can get all the values that has changed and only those one.
For example,
this.form = this.formBuilder.group({
name: '',
age: '',
city: ''
});
In my html template, I would like to have 3 inputs, one for each formcontrol of my form. I also want to have a button, when I click on it, the resulting action should be sending to my backend only the changed values (PATCH method).
I don't see how we can do this. I've tried with the observable 'valueChanges', but it returns the whole form and I don't see how it can help me.
Any idea ?
Thanks !
angular angular asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
asked Nov 22 '18 at 23:48
DarkkradDarkkrad
102
102
Take a snapshot of the form when you populate it first. Compare with that snapshot before submitting.
– JB Nizet
Nov 22 '18 at 23:56
add a comment |
Take a snapshot of the form when you populate it first. Compare with that snapshot before submitting.
– JB Nizet
Nov 22 '18 at 23:56
Take a snapshot of the form when you populate it first. Compare with that snapshot before submitting.
– JB Nizet
Nov 22 '18 at 23:56
Take a snapshot of the form when you populate it first. Compare with that snapshot before submitting.
– JB Nizet
Nov 22 '18 at 23:56
add a comment |
1 Answer
1
active
oldest
votes
So here's a workaround that I've been using for sometime and it's working.
Suppose you have form of type FormBuilder and the initial values of each part of the form are stored in info obj. For example, our form has only a username and an email.
in ngOnInit, we subscribe to any changes:
this.form.valueChanges.subscribe(dt => this.fieldChanges());
then we implement the method:
fieldChanges() {
this.anyChanges = false;
let username = this.form.controls['username'] && this.form.controls['username'].value || '';
let email = this.form.controls['email'] && this.form.controls['email'].value || '';
if (this.info['username'] !== username.trim() || this.info['email'] !== email.trim()) {
this.anyChanges = true;
}
}
From this code, if there exists any changes, the anyChange property will be set to true. If you separate the conditions, you can access all the changes for individual form control elements. But if you only care about whether there was any changes, you can use a shorter version of the code above, using Object.keys(info).forEach(...) and then you will be able to detect changes in a more generalized and better way. Or if you wish to store the fields that've been changed, you can define an object and in the forEach part, you add the keys and values of the changed fields to this object. At the end, you have an object of changed fields with their old/new values, as needed.
answered Nov 23 '18 at 0:08
imans77imans77
432313
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53439181%2fangular-6-get-all-changed-values-on-formgroup%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
So here's a workaround that I've been using for sometime and it's working.
Suppose you have form of type FormBuilder and the initial values of each part of the form are stored in info obj. For example, our form has only a username and an email.
in ngOnInit, we subscribe to any changes:
this.form.valueChanges.subscribe(dt => this.fieldChanges());
then we implement the method:
fieldChanges() {
this.anyChanges = false;
let username = this.form.controls['username'] && this.form.controls['username'].value || '';
let email = this.form.controls['email'] && this.form.controls['email'].value || '';
if (this.info['username'] !== username.trim() || this.info['email'] !== email.trim()) {
this.anyChanges = true;
}
}
From this code, if there exists any changes, the anyChange property will be set to true. If you separate the conditions, you can access all the changes for individual form control elements. But if you only care about whether there was any changes, you can use a shorter version of the code above, using Object.keys(info).forEach(...) and then you will be able to detect changes in a more generalized and better way. Or if you wish to store the fields that've been changed, you can define an object and in the forEach part, you add the keys and values of the changed fields to this object. At the end, you have an object of changed fields with their old/new values, as needed.
answered Nov 23 '18 at 0:08
imans77imans77
432313
add a comment |
So here's a workaround that I've been using for sometime and it's working.
Suppose you have form of type FormBuilder and the initial values of each part of the form are stored in info obj. For example, our form has only a username and an email.
in ngOnInit, we subscribe to any changes:
this.form.valueChanges.subscribe(dt => this.fieldChanges());
then we implement the method:
fieldChanges() {
this.anyChanges = false;
let username = this.form.controls['username'] && this.form.controls['username'].value || '';
let email = this.form.controls['email'] && this.form.controls['email'].value || '';
if (this.info['username'] !== username.trim() || this.info['email'] !== email.trim()) {
this.anyChanges = true;
}
}
From this code, if there exists any changes, the anyChange property will be set to true. If you separate the conditions, you can access all the changes for individual form control elements. But if you only care about whether there was any changes, you can use a shorter version of the code above, using Object.keys(info).forEach(...) and then you will be able to detect changes in a more generalized and better way. Or if you wish to store the fields that've been changed, you can define an object and in the forEach part, you add the keys and values of the changed fields to this object. At the end, you have an object of changed fields with their old/new values, as needed.
answered Nov 23 '18 at 0:08
imans77imans77
432313
add a comment |
So here's a workaround that I've been using for sometime and it's working.
Suppose you have form of type FormBuilder and the initial values of each part of the form are stored in info obj. For example, our form has only a username and an email.
in ngOnInit, we subscribe to any changes:
this.form.valueChanges.subscribe(dt => this.fieldChanges());
then we implement the method:
fieldChanges() {
this.anyChanges = false;
let username = this.form.controls['username'] && this.form.controls['username'].value || '';
let email = this.form.controls['email'] && this.form.controls['email'].value || '';
if (this.info['username'] !== username.trim() || this.info['email'] !== email.trim()) {
this.anyChanges = true;
}
}
From this code, if there exists any changes, the anyChange property will be set to true. If you separate the conditions, you can access all the changes for individual form control elements. But if you only care about whether there was any changes, you can use a shorter version of the code above, using Object.keys(info).forEach(...) and then you will be able to detect changes in a more generalized and better way. Or if you wish to store the fields that've been changed, you can define an object and in the forEach part, you add the keys and values of the changed fields to this object. At the end, you have an object of changed fields with their old/new values, as needed.
answered Nov 23 '18 at 0:08
imans77imans77
432313
So here's a workaround that I've been using for sometime and it's working.
Suppose you have form of type FormBuilder and the initial values of each part of the form are stored in info obj. For example, our form has only a username and an email.
in ngOnInit, we subscribe to any changes:
this.form.valueChanges.subscribe(dt => this.fieldChanges());
then we implement the method:
fieldChanges() {
this.anyChanges = false;
let username = this.form.controls['username'] && this.form.controls['username'].value || '';
let email = this.form.controls['email'] && this.form.controls['email'].value || '';
if (this.info['username'] !== username.trim() || this.info['email'] !== email.trim()) {
this.anyChanges = true;
}
}
From this code, if there exists any changes, the anyChange property will be set to true. If you separate the conditions, you can access all the changes for individual form control elements. But if you only care about whether there was any changes, you can use a shorter version of the code above, using Object.keys(info).forEach(...) and then you will be able to detect changes in a more generalized and better way. Or if you wish to store the fields that've been changed, you can define an object and in the forEach part, you add the keys and values of the changed fields to this object. At the end, you have an object of changed fields with their old/new values, as needed.
answered Nov 23 '18 at 0:08
imans77imans77
432313
answered Nov 23 '18 at 0:08
imans77imans77
432313
answered Nov 23 '18 at 0:08
imans77imans77
432313
answered Nov 23 '18 at 0:08
imans77imans77
432313
432313
add a comment |
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53439181%2fangular-6-get-all-changed-values-on-formgroup%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Take a snapshot of the form when you populate it first. Compare with that snapshot before submitting.
– JB Nizet
Nov 22 '18 at 23:56