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Add proper autocompletion functionality.

This commit is contained in:
Bauke 2023-12-17 13:22:20 +01:00
parent f56f82b9f0
commit 9f8dc481da
Signed by: Bauke
GPG Key ID: C1C0F29952BCF558
2 changed files with 160 additions and 34 deletions

View File

@ -33,6 +33,12 @@ type State = {
/** The position where the group autocompletion list should be shown. */
groupsPosition: Offset | undefined;
/** The currently highlighted match index of the active list. */
highlightedIndex: number;
/** Whether the user is currently typing in an autocomplete section. */
typingInAutocomplete: boolean;
/** All the usernames without leading @-symbols. */
usernames: Set<string>;
@ -46,6 +52,27 @@ type State = {
usernamesPosition: Offset | undefined;
};
/** All the properties we need to handle `<textarea>` input. */
type TextareaInputProps = {
/** Which key is being pressed. */
key: string;
/** The prefix for the autocomplete to detect. */
prefix: "~" | "@";
/** Whether SHIFT is being pressed. */
shift: boolean;
/** The list of values we are targetting. */
target: "groups" | "usernames";
/** The `<textarea>` element. */
textarea: HTMLTextAreaElement;
/** The current set of values to match against. */
values: Set<string>;
};
export class AutocompleteFeature extends Component<Props, State> {
constructor(props: Props) {
super(props);
@ -73,6 +100,8 @@ export class AutocompleteFeature extends Component<Props, State> {
groupsHidden: true,
groupsMatches: new Set(groups),
groupsPosition: undefined,
highlightedIndex: 0,
typingInAutocomplete: false,
usernames: new Set(usernames),
usernamesHidden: true,
usernamesMatches: new Set(usernames),
@ -102,42 +131,63 @@ export class AutocompleteFeature extends Component<Props, State> {
return;
}
// Get the key that was pressed.
const [key, shift] =
event instanceof KeyboardEvent
? [event.key, event.shiftKey]
: [event.data, false];
if (this.state.typingInAutocomplete && ["Enter", "Tab"].includes(key)) {
// If the user is typing with an autocomplete list active then prevent
// certain keys from taking effect, like Tab moving the focus away.
event.preventDefault();
}
// Helper function to create autocompletes with.
const createHandler = (
prefix: string,
target: string,
values: Set<string>,
prefix: TextareaInputProps["prefix"],
target: TextareaInputProps["target"],
values: TextareaInputProps["values"],
) => {
const dataAttribute = `data-trx-autocomplete-${target}`;
// Get the key that was pressed.
const key = event instanceof KeyboardEvent ? event.key : event.data;
if (key === prefix && !textarea.getAttribute(dataAttribute)) {
textarea.setAttribute(dataAttribute, "true");
textarea.addEventListener("keyup", (event) => {
if (!(event.target instanceof HTMLTextAreaElement)) {
return;
}
this.textareaInputHandler(event.target, prefix, target, values);
textarea.addEventListener("keyup", (innerEvent) => {
this.textareaInputHandler({
key: innerEvent.key,
prefix,
shift: innerEvent.shiftKey,
target,
textarea,
values,
});
});
this.textareaInputHandler(textarea, prefix, target, values);
this.textareaInputHandler({
key,
prefix,
shift,
target,
textarea,
values,
});
}
};
createHandler("~", "groups", this.state.groups);
createHandler("@", "usernames", this.state.usernames);
if (["~", "@"].includes(key)) {
// When an autocomplete is first started manually set that we're typing
// in it.
this.setState({typingInAutocomplete: true});
}
};
/** The input handler for any `<textarea>` elements. */
textareaInputHandler = (
textarea: HTMLTextAreaElement,
prefix: string,
target: string,
values: Set<string>,
) => {
textareaInputHandler = (props: TextareaInputProps) => {
const {key, prefix, shift, target, textarea, values} = props;
const text = textarea.value;
// If the prefix isn't in the textarea, return early.
@ -161,7 +211,13 @@ export class AutocompleteFeature extends Component<Props, State> {
// groups cannot have whitespace in them which means that the user has
// finished typing what the autocomplete should handle.
if (/\s/.test(input)) {
this.hide(target);
if (key === " " || key === "Backspace") {
// If Space or Backspace were pressed and there was nothing between the
// prefix and current cursor position then it means we don't want to
// continue showing the autocomplete list.
this.hide(target);
}
return;
}
@ -178,14 +234,63 @@ export class AutocompleteFeature extends Component<Props, State> {
return;
}
// Otherwise make sure the list is shown in the correct place and also
// has all the new matches.
this.show(target, offset(textarea));
this.update(target, matches);
let {highlightedIndex} = this.state;
if (key === "Enter") {
// Grab the highlighted match.
const highlightedMatch = Array.from(matches)[highlightedIndex];
if (highlightedMatch === undefined) {
log(
`Autocomplete: Attempted to enter undefined match with index ${highlightedIndex}`,
true,
);
return;
}
// Then insert it into the textarea.
textarea.value =
// First grab the existing text up to and including the current prefix.
text.slice(0, prefixIndex + prefix.length) +
// Then add the highlighted match.
highlightedMatch +
// And finally add the existing text where the cursor was positioned.
text.slice(position);
this.hide(target);
highlightedIndex = 0;
// Set the cursor position to the end of the autocompleted match.
const newPosition = prefixIndex + prefix.length + highlightedMatch.length;
textarea.selectionStart = newPosition;
textarea.selectionEnd = newPosition;
} else if (key === "Tab") {
if (shift) {
// If shift is being pressed move the highlight back up.
highlightedIndex -= 1;
} else {
// Otherwise with just tab being pressed move it down.
highlightedIndex += 1;
}
} else {
// When any other key is pressed make sure the list is shown in the
// correct place and also has all the new matches.
this.show(target, offset(textarea));
this.update(target, matches);
}
// Make sure the highlighted index is never set out of bounds.
if (highlightedIndex < 0) {
highlightedIndex = matches.size - 1;
} else if (highlightedIndex >= matches.size) {
highlightedIndex = 0;
}
this.setState({highlightedIndex});
};
/** Update the available matches. */
update = (target: string, matches: Set<string>) => {
update = (
target: TextareaInputProps["target"],
matches: TextareaInputProps["values"],
) => {
if (target === "groups") {
this.setState({
groupsMatches: matches,
@ -198,36 +303,46 @@ export class AutocompleteFeature extends Component<Props, State> {
};
/** Show the autocomplete list in the given position. */
show = (target: string, position: Offset) => {
show = (target: TextareaInputProps["target"], position: Offset) => {
if (target === "groups") {
this.setState({
groupsHidden: false,
groupsPosition: position,
typingInAutocomplete: true,
});
} else if (target === "usernames") {
this.setState({
usernamesHidden: false,
usernamesPosition: position,
typingInAutocomplete: true,
});
}
};
/** Hide the autocomplete list. */
hide = (target: string) => {
hide = (target: TextareaInputProps["target"]) => {
if (target === "groups") {
this.setState({groupsHidden: true});
this.setState({
groupsHidden: true,
typingInAutocomplete: false,
});
} else if (target === "usernames") {
this.setState({usernamesHidden: true});
this.setState({
usernamesHidden: true,
typingInAutocomplete: false,
});
}
};
render() {
const {groupsMatches, highlightedIndex, usernamesMatches} = this.state;
// Create the `<li>` elements for groups and usernames.
const groups = [...this.state.groupsMatches].map((value) => (
<li>~{value}</li>
const groups = [...groupsMatches].map((value, index) => (
<li class={highlightedIndex === index ? "highlighted" : ""}>~{value}</li>
));
const usernames = [...this.state.usernamesMatches].map((value) => (
<li>@{value}</li>
const usernames = [...usernamesMatches].map((value, index) => (
<li class={highlightedIndex === index ? "highlighted" : ""}>@{value}</li>
));
// Figure out which lists are hidden.

View File

@ -4,10 +4,21 @@
font-size: 80%;
max-height: 8rem;
overflow-x: hidden;
overflow-y: auto;
overflow-y: hidden;
position: absolute;
li {
margin: 0;
&.highlighted {
align-items: center;
background-color: var(--background-primary-color);
display: flex;
&::after {
content: '';
margin-left: auto;
}
}
}
}