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svelte/src/generators/dom/index.ts

255 lines
8.8 KiB

import MagicString from 'magic-string';
import { parseExpressionAt } from 'acorn';
import annotateWithScopes from '../../utils/annotateWithScopes';
import isReference from '../../utils/isReference';
import { walk } from 'estree-walker';
import deindent from '../../utils/deindent.js';
import CodeBuilder from '../../utils/CodeBuilder';
import visit from './visit';
import shared from './shared';
import Generator from '../Generator';
import preprocess from './preprocess';
class DomGenerator extends Generator {
constructor ( parsed, source, name, options ) {
super( parsed, source, name, options );
this.blocks = [];
this.uses = new Set();
this.readonly = new Set();
// initial values for e.g. window.innerWidth, if there's a <:Window> meta tag
this.metaBindings = [];
}
helper ( name ) {
if ( this.options.dev && `${name}Dev` in shared ) {
name = `${name}Dev`;
}
this.uses.add( name );
return this.alias( name );
}
}
export default function dom ( parsed, source, options ) {
const format = options.format || 'es';
const name = options.name || 'SvelteComponent';
const generator = new DomGenerator( parsed, source, name, options );
const { computations, hasJs, templateProperties, namespace } = generator.parseJs();
const state = {
namespace,
parentNode: null,
isTopLevel: true
};
const block = preprocess( generator, state, parsed.html );
parsed.html.children.forEach( node => {
visit( generator, block, state, node );
});
const builders = {
main: new CodeBuilder(),
_set: new CodeBuilder()
};
if ( computations.length ) {
const builder = new CodeBuilder();
const differs = generator.helper( 'differs' );
computations.forEach( ({ key, deps }) => {
if ( generator.readonly.has( key ) ) {
// <:Window> bindings
throw new Error( `Cannot have a computed value '${key}' that clashes with a read-only property` );
}
generator.readonly.add( key );
const condition = `isInitial || ${deps.map( dep => `( '${dep}' in newState && ${differs}( state.${dep}, oldState.${dep} ) )` ).join( ' || ' )}`;
const statement = `state.${key} = newState.${key} = ${generator.alias( 'template' )}.computed.${key}( ${deps.map( dep => `state.${dep}` ).join( ', ' )} );`;
builder.addConditionalLine( condition, statement );
});
builders.main.addBlock( deindent`
function ${generator.alias( 'recompute' )} ( state, newState, oldState, isInitial ) {
${builder}
}
` );
}
builders._set.addBlock( deindent`
${options.dev && deindent`
if ( typeof newState !== 'object' ) {
throw new Error( 'Component .set was called without an object of data key-values to update.' );
}
${Array.from( generator.readonly ).map( prop =>
`if ( '${prop}' in newState && !this._updatingReadonlyProperty ) throw new Error( "Cannot set read-only property '${prop}'" );`
)}
`}
var oldState = this._state;
this._state = ${generator.helper( 'assign' )}( {}, oldState, newState );
${computations.length && `${generator.alias( 'recompute' )}( this._state, newState, oldState, false )`}
${generator.helper( 'dispatchObservers' )}( this, this._observers.pre, newState, oldState );
${block.hasUpdateMethod && `this._fragment.update( newState, this._state );`}
${generator.helper( 'dispatchObservers' )}( this, this._observers.post, newState, oldState );
${generator.hasComplexBindings && `while ( this._bindings.length ) this._bindings.pop()();`}
${( generator.hasComponents || generator.hasIntroTransitions ) && `this._flush();`}
` );
if ( hasJs ) {
builders.main.addBlock( `[✂${parsed.js.content.start}-${parsed.js.content.end}✂]` );
}
if ( generator.css && options.css !== false ) {
builders.main.addBlock( deindent`
function ${generator.alias( 'add_css' )} () {
var style = ${generator.helper( 'createElement' )}( 'style' );
style.id = ${JSON.stringify( generator.cssId + '-style' )};
style.textContent = ${JSON.stringify( generator.css )};
${generator.helper( 'appendNode' )}( style, document.head );
}
` );
}
generator.blocks.forEach( block => {
builders.main.addBlock( block.render() );
});
const sharedPath = options.shared === true ? 'svelte/shared.js' : options.shared;
const prototypeBase = `${name}.prototype` + ( templateProperties.methods ? `, ${generator.alias( 'template' )}.methods` : '' );
const proto = sharedPath ? `${generator.helper( 'proto' )} ` : deindent`
{
${
[ 'get', 'fire', 'observe', 'on', 'set', '_flush' ]
.map( n => `${n}: ${generator.helper( n )}` )
.join( ',\n' )
}
}`;
// TODO deprecate component.teardown()
builders.main.addBlock( deindent`
function ${name} ( options ) {
options = options || {};
${options.dev && `if ( !options.target && !options._root ) throw new Error( "'target' is a required option" );`}
${generator.usesRefs && `this.refs = {};`}
this._state = ${templateProperties.data ? `${generator.helper( 'assign' )}( ${generator.alias( 'template' )}.data(), options.data )` : `options.data || {}`};
${generator.metaBindings}
${computations.length && `${generator.alias( 'recompute' )}( this._state, this._state, {}, true );`}
${options.dev && Array.from( generator.expectedProperties ).map( prop => `if ( !( '${prop}' in this._state ) ) console.warn( "Component was created without expected data property '${prop}'" );`)}
${generator.bindingGroups.length && `this._bindingGroups = [ ${Array( generator.bindingGroups.length ).fill( '[]' ).join( ', ' )} ];`}
this._observers = {
pre: Object.create( null ),
post: Object.create( null )
};
this._handlers = Object.create( null );
this._root = options._root || this;
this._yield = options._yield;
this._torndown = false;
${parsed.css && options.css !== false && `if ( !document.getElementById( ${JSON.stringify( generator.cssId + '-style' )} ) ) ${generator.alias( 'add_css' )}();`}
${( generator.hasComponents || generator.hasIntroTransitions ) && `this._renderHooks = [];`}
${generator.hasComplexBindings && `this._bindings = [];`}
this._fragment = ${generator.alias( 'create_main_fragment' )}( this._state, this );
if ( options.target ) this._fragment.mount( options.target, null );
${generator.hasComplexBindings && `while ( this._bindings.length ) this._bindings.pop()();`}
${( generator.hasComponents || generator.hasIntroTransitions ) && `this._flush();`}
${templateProperties.oncreate && deindent`
if ( options._root ) {
options._root._renderHooks.push( ${generator.alias( 'template' )}.oncreate.bind( this ) );
} else {
${generator.alias( 'template' )}.oncreate.call( this );
}
`}
}
${generator.helper( 'assign' )}( ${prototypeBase}, ${proto});
${name}.prototype._set = function _set ( newState ) {
${builders._set}
};
${name}.prototype.teardown = ${name}.prototype.destroy = function destroy ( detach ) {
this.fire( 'destroy' );
${templateProperties.ondestroy && `${generator.alias( 'template' )}.ondestroy.call( this );`}
this._fragment.destroy( detach !== false );
this._fragment = null;
this._state = {};
this._torndown = true;
};
` );
if ( sharedPath ) {
if ( format !== 'es' ) {
throw new Error( `Components with shared helpers must be compiled to ES2015 modules (format: 'es')` );
}
const names = Array.from( generator.uses ).sort().map( name => {
return name !== generator.alias( name ) ? `${name} as ${generator.alias( name )}` : name;
});
builders.main.addLineAtStart(
`import { ${names.join( ', ' )} } from ${JSON.stringify( sharedPath )};`
);
} else {
generator.uses.forEach( key => {
const str = shared[ key ];
const code = new MagicString( str );
const expression = parseExpressionAt( str, 0 );
let scope = annotateWithScopes( expression );
walk( expression, {
enter ( node, parent ) {
if ( node._scope ) scope = node._scope;
if ( node.type === 'Identifier' && isReference( node, parent ) && !scope.has( node.name ) ) {
if ( node.name in shared ) {
// this helper function depends on another one
const dependency = node.name;
generator.uses.add( dependency );
const alias = generator.alias( dependency );
if ( alias !== node.name ) code.overwrite( node.start, node.end, alias );
}
}
},
leave ( node ) {
if ( node._scope ) scope = scope.parent;
}
});
if ( key === 'transitionManager' ) { // special case
const global = `_svelteTransitionManager`;
builders.main.addBlock(
`var ${generator.alias( 'transitionManager' )} = window.${global} || ( window.${global} = ${code});`
);
} else {
const alias = generator.alias( expression.id.name );
if ( alias !== expression.id.name ) code.overwrite( expression.id.start, expression.id.end, alias );
builders.main.addBlock( code.toString() );
}
});
}
return generator.generate( builders.main.toString(), options, { name, format } );
}