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svelte/src/generators/nodes/IfBlock.ts

498 lines
12 KiB

import deindent from '../../utils/deindent';
import Node from './shared/Node';
import ElseBlock from './ElseBlock';
import { DomGenerator } from '../dom/index';
import Block from '../dom/Block';
import createDebuggingComment from '../../utils/createDebuggingComment';
function isElseIf(node: ElseBlock) {
return (
node && node.children.length === 1 && node.children[0].type === 'IfBlock'
);
}
function isElseBranch(branch) {
return branch.block && !branch.condition;
}
export default class IfBlock extends Node {
type: 'IfBlock';
else: ElseBlock;
block: Block;
init(
block: Block,
stripWhitespace: boolean,
nextSibling: Node
) {
const { generator } = this;
this.cannotUseInnerHTML();
const blocks: Block[] = [];
let dynamic = false;
let hasIntros = false;
let hasOutros = false;
function attachBlocks(node: IfBlock) {
node.var = block.getUniqueName(`if_block`);
block.addDependencies(node.metadata.dependencies);
node.block = block.child({
comment: createDebuggingComment(node, generator),
name: generator.getUniqueName(`create_if_block`),
});
blocks.push(node.block);
node.initChildren(node.block, stripWhitespace, nextSibling);
if (node.block.dependencies.size > 0) {
dynamic = true;
block.addDependencies(node.block.dependencies);
}
if (node.block.hasIntroMethod) hasIntros = true;
if (node.block.hasOutroMethod) hasOutros = true;
if (isElseIf(node.else)) {
attachBlocks(node.else.children[0]);
} else if (node.else) {
node.else.block = block.child({
comment: createDebuggingComment(node.else, generator),
name: generator.getUniqueName(`create_if_block`),
});
blocks.push(node.else.block);
node.else.initChildren(
node.else.block,
stripWhitespace,
nextSibling
);
if (node.else.block.dependencies.size > 0) {
dynamic = true;
block.addDependencies(node.else.block.dependencies);
}
}
}
attachBlocks(this);
blocks.forEach(block => {
block.hasUpdateMethod = dynamic;
block.hasIntroMethod = hasIntros;
block.hasOutroMethod = hasOutros;
});
generator.blocks.push(...blocks);
}
build(
block: Block,
parentNode: string,
parentNodes: string
) {
const name = this.var;
const needsAnchor = this.next ? !this.next.isDomNode() : !parentNode || !this.parent.isDomNode();
const anchor = needsAnchor
? block.getUniqueName(`${name}_anchor`)
: (this.next && this.next.var) || 'null';
const params = block.params.join(', ');
const branches = getBranches(this.generator, block, parentNode, parentNodes, this);
const hasElse = isElseBranch(branches[branches.length - 1]);
const if_name = hasElse ? '' : `if (${name}) `;
const dynamic = branches[0].hasUpdateMethod; // can use [0] as proxy for all, since they necessarily have the same value
const hasOutros = branches[0].hasOutroMethod;
const vars = { name, anchor, params, if_name, hasElse };
if (this.else) {
if (hasOutros) {
compoundWithOutros(
this.generator,
block,
parentNode,
parentNodes,
this,
branches,
dynamic,
vars
);
} else {
compound(this.generator, block, parentNode, parentNodes, this, branches, dynamic, vars);
}
} else {
simple(this.generator, block, parentNode, parentNodes, this, branches[0], dynamic, vars);
}
block.builders.create.addLine(`${if_name}${name}.c();`);
block.builders.claim.addLine(
`${if_name}${name}.l(${parentNodes});`
);
if (needsAnchor) {
block.addElement(
anchor,
`@createComment()`,
`@createComment()`,
parentNode
);
}
}
}
// TODO move all this into the class
function getBranches(
generator: DomGenerator,
block: Block,
parentNode: string,
parentNodes: string,
node: Node
) {
block.contextualise(node.expression); // TODO remove
const branches = [
{
condition: node.metadata.snippet,
block: node.block.name,
hasUpdateMethod: node.block.hasUpdateMethod,
hasIntroMethod: node.block.hasIntroMethod,
hasOutroMethod: node.block.hasOutroMethod,
},
];
visitChildren(generator, block, node);
if (isElseIf(node.else)) {
branches.push(
...getBranches(generator, block, parentNode, parentNodes, node.else.children[0])
);
} else {
branches.push({
condition: null,
block: node.else ? node.else.block.name : null,
hasUpdateMethod: node.else ? node.else.block.hasUpdateMethod : false,
hasIntroMethod: node.else ? node.else.block.hasIntroMethod : false,
hasOutroMethod: node.else ? node.else.block.hasOutroMethod : false,
});
if (node.else) {
visitChildren(generator, block, node.else);
}
}
return branches;
}
function visitChildren(
generator: DomGenerator,
block: Block,
node: Node
) {
node.children.forEach((child: Node) => {
child.build(node.block, null, 'nodes');
});
}
function simple(
generator: DomGenerator,
block: Block,
parentNode: string,
parentNodes: string,
node: Node,
branch,
dynamic,
{ name, anchor, params, if_name }
) {
block.builders.init.addBlock(deindent`
var ${name} = (${branch.condition}) && ${branch.block}(${params}, #component);
`);
const mountOrIntro = branch.hasIntroMethod ? 'i' : 'm';
const initialMountNode = parentNode || '#target';
const anchorNode = parentNode ? 'null' : 'anchor';
block.builders.mount.addLine(
`if (${name}) ${name}.${mountOrIntro}(${initialMountNode}, ${anchorNode});`
);
const updateMountNode = node.getUpdateMountNode(anchor);
const enter = dynamic
? branch.hasIntroMethod
? deindent`
if (${name}) {
${name}.p(changed, ${params});
} else {
${name} = ${branch.block}(${params}, #component);
if (${name}) ${name}.c();
}
${name}.i(${updateMountNode}, ${anchor});
`
: deindent`
if (${name}) {
${name}.p(changed, ${params});
} else {
${name} = ${branch.block}(${params}, #component);
${name}.c();
${name}.m(${updateMountNode}, ${anchor});
}
`
: branch.hasIntroMethod
? deindent`
if (!${name}) {
${name} = ${branch.block}(${params}, #component);
${name}.c();
}
${name}.i(${updateMountNode}, ${anchor});
`
: deindent`
if (!${name}) {
${name} = ${branch.block}(${params}, #component);
${name}.c();
${name}.m(${updateMountNode}, ${anchor});
}
`;
// no `p()` here — we don't want to update outroing nodes,
// as that will typically result in glitching
const exit = branch.hasOutroMethod
? deindent`
${name}.o(function() {
${name}.u();
${name}.d();
${name} = null;
});
`
: deindent`
${name}.u();
${name}.d();
${name} = null;
`;
block.builders.update.addBlock(deindent`
if (${branch.condition}) {
${enter}
} else if (${name}) {
${exit}
}
`);
block.builders.unmount.addLine(`${if_name}${name}.u();`);
block.builders.destroy.addLine(`${if_name}${name}.d();`);
}
function compound(
generator: DomGenerator,
block: Block,
parentNode: string,
parentNodes: string,
node: Node,
branches,
dynamic,
{ name, anchor, params, hasElse, if_name }
) {
const select_block_type = generator.getUniqueName(`select_block_type`);
const current_block_type = block.getUniqueName(`current_block_type`);
const current_block_type_and = hasElse ? '' : `${current_block_type} && `;
generator.blocks.push(deindent`
function ${select_block_type}(${params}) {
${branches
.map(({ condition, block }) => `${condition ? `if (${condition}) ` : ''}return ${block};`)
.join('\n')}
}
`);
block.builders.init.addBlock(deindent`
var ${current_block_type} = ${select_block_type}(${params});
var ${name} = ${current_block_type_and}${current_block_type}(${params}, #component);
`);
const mountOrIntro = branches[0].hasIntroMethod ? 'i' : 'm';
const initialMountNode = parentNode || '#target';
const anchorNode = parentNode ? 'null' : 'anchor';
block.builders.mount.addLine(
`${if_name}${name}.${mountOrIntro}(${initialMountNode}, ${anchorNode});`
);
const updateMountNode = node.getUpdateMountNode(anchor);
const changeBlock = deindent`
${hasElse
? deindent`
${name}.u();
${name}.d();
`
: deindent`
if (${name}) {
${name}.u();
${name}.d();
}`}
${name} = ${current_block_type_and}${current_block_type}(${params}, #component);
${if_name}${name}.c();
${if_name}${name}.${mountOrIntro}(${updateMountNode}, ${anchor});
`;
if (dynamic) {
block.builders.update.addBlock(deindent`
if (${current_block_type} === (${current_block_type} = ${select_block_type}(${params})) && ${name}) {
${name}.p(changed, ${params});
} else {
${changeBlock}
}
`);
} else {
block.builders.update.addBlock(deindent`
if (${current_block_type} !== (${current_block_type} = ${select_block_type}(${params}))) {
${changeBlock}
}
`);
}
block.builders.unmount.addLine(`${if_name}${name}.u();`);
block.builders.destroy.addLine(`${if_name}${name}.d();`);
}
// if any of the siblings have outros, we need to keep references to the blocks
// (TODO does this only apply to bidi transitions?)
function compoundWithOutros(
generator: DomGenerator,
block: Block,
parentNode: string,
parentNodes: string,
node: Node,
branches,
dynamic,
{ name, anchor, params, hasElse }
) {
const select_block_type = block.getUniqueName(`select_block_type`);
const current_block_type_index = block.getUniqueName(`current_block_type_index`);
const previous_block_index = block.getUniqueName(`previous_block_index`);
const if_block_creators = block.getUniqueName(`if_block_creators`);
const if_blocks = block.getUniqueName(`if_blocks`);
const if_current_block_type_index = hasElse
? ''
: `if (~${current_block_type_index}) `;
block.addVariable(current_block_type_index);
block.addVariable(name);
block.builders.init.addBlock(deindent`
var ${if_block_creators} = [
${branches.map(branch => branch.block).join(',\n')}
];
var ${if_blocks} = [];
function ${select_block_type}(${params}) {
${branches
.map(({ condition, block }, i) => `${condition ? `if (${condition}) ` : ''}return ${block ? i : -1};`)
.join('\n')}
}
`);
if (hasElse) {
block.builders.init.addBlock(deindent`
${current_block_type_index} = ${select_block_type}(${params});
${name} = ${if_blocks}[${current_block_type_index}] = ${if_block_creators}[${current_block_type_index}](${params}, #component);
`);
} else {
block.builders.init.addBlock(deindent`
if (~(${current_block_type_index} = ${select_block_type}(${params}))) {
${name} = ${if_blocks}[${current_block_type_index}] = ${if_block_creators}[${current_block_type_index}](${params}, #component);
}
`);
}
const mountOrIntro = branches[0].hasIntroMethod ? 'i' : 'm';
const initialMountNode = parentNode || '#target';
const anchorNode = parentNode ? 'null' : 'anchor';
block.builders.mount.addLine(
`${if_current_block_type_index}${if_blocks}[${current_block_type_index}].${mountOrIntro}(${initialMountNode}, ${anchorNode});`
);
const updateMountNode = node.getUpdateMountNode(anchor);
const destroyOldBlock = deindent`
${name}.o(function() {
${if_blocks}[ ${previous_block_index} ].u();
${if_blocks}[ ${previous_block_index} ].d();
${if_blocks}[ ${previous_block_index} ] = null;
});
`;
const createNewBlock = deindent`
${name} = ${if_blocks}[${current_block_type_index}];
if (!${name}) {
${name} = ${if_blocks}[${current_block_type_index}] = ${if_block_creators}[${current_block_type_index}](${params}, #component);
${name}.c();
}
${name}.${mountOrIntro}(${updateMountNode}, ${anchor});
`;
const changeBlock = hasElse
? deindent`
${destroyOldBlock}
${createNewBlock}
`
: deindent`
if (${name}) {
${destroyOldBlock}
}
if (~${current_block_type_index}) {
${createNewBlock}
} else {
${name} = null;
}
`;
if (dynamic) {
block.builders.update.addBlock(deindent`
var ${previous_block_index} = ${current_block_type_index};
${current_block_type_index} = ${select_block_type}(${params});
if (${current_block_type_index} === ${previous_block_index}) {
${if_current_block_type_index}${if_blocks}[${current_block_type_index}].p(changed, ${params});
} else {
${changeBlock}
}
`);
} else {
block.builders.update.addBlock(deindent`
var ${previous_block_index} = ${current_block_type_index};
${current_block_type_index} = ${select_block_type}(${params});
if (${current_block_type_index} !== ${previous_block_index}) {
${changeBlock}
}
`);
}
block.builders.destroy.addLine(deindent`
${if_current_block_type_index}{
${if_blocks}[${current_block_type_index}].u();
${if_blocks}[${current_block_type_index}].d();
}
`);
}