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svelte/compiler/generate/visitors/IfBlock.js

116 lines
3.0 KiB

import deindent from '../utils/deindent.js';
import counter from '../utils/counter.js';
export default {
enter ( generator, node ) {
const i = generator.counters.if++;
const name = `ifBlock_${i}`;
const renderer = `renderIfBlock_${i}`;
const elseName = `elseBlock_${i}`;
const elseRenderer = `renderElseBlock_${i}`;
generator.addSourcemapLocations( node.expression );
const { snippet, string } = generator.contextualise( node.expression );
generator.current.initStatements.push( deindent`
var ${name}_anchor = document.createComment( ${JSON.stringify( `#if ${generator.source.slice( node.expression.start, node.expression.end )}` )} );
${generator.current.target}.appendChild( ${name}_anchor );
` );
if ( node.else ) {
generator.current.initStatements.push( deindent`
var ${name} = null;
var ${elseName} = null;
if ( ${snippet} ) {
${name} = ${renderer}( ${generator.current.params}, component, ${generator.current.target}, ${name}_anchor );
} else {
${elseName} = ${elseRenderer}( ${generator.current.params}, component, ${generator.current.target}, ${name}_anchor );
}
` );
} else {
generator.current.initStatements.push( deindent`
var ${name} = ${snippet} ? ${renderer}( ${generator.current.params}, component, ${generator.current.target}, ${name}_anchor ) : null;
` );
}
const ifTrue = [ deindent`
if ( !${name } ) {
${name} = ${renderer}( ${generator.current.params}, component, ${generator.current.target}, ${name}_anchor );
} else {
${name}.update( changed, ${generator.current.params} );
}
` ];
if ( node.else ) {
ifTrue.push( deindent`
if ( ${elseName } ) {
${elseName}.teardown();
${elseName} = null;
}
` );
}
const ifFalse = [ deindent`
if ( ${name} ) {
${name}.teardown();
${name} = null;
}
` ];
if ( node.else ) {
ifFalse.push( deindent`
if ( !${elseName } ) {
${elseName} = ${elseRenderer}( ${generator.current.params}, component, ${generator.current.target}, ${name}_anchor );
} else {
${elseName}.update( changed, ${generator.current.params} );
}
` );
}
let update = deindent`
if ( ${string} ) {
${ifTrue.join( '\n\n' )}
}
else {
${ifFalse.join( '\n\n' )}
}
`;
if ( node.else ) {
update += `\nif ( ${elseName} ) ${elseName}.update( changed, ${generator.current.params} );`;
}
generator.current.updateStatements.push( update );
generator.current.teardownStatements.push( deindent`
if ( ${name} ) ${name}.teardown();${node.else ? `\nif ( ${elseName} ) ${elseName}.teardown();` : ``}
${name}_anchor.parentNode.removeChild( ${name}_anchor );
` );
generator.push({
useAnchor: true,
name: renderer,
target: 'target',
initStatements: [],
updateStatements: [],
teardownStatements: [],
counter: counter()
});
},
leave ( generator, node ) {
generator.addRenderer( generator.current );
if ( node.else ) {
generator.visit( node.else );
}
generator.pop();
}
};