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svelte/src/generators/dom/visitors/EachBlock.ts

492 lines
13 KiB

import deindent from '../../../utils/deindent';
import visit from '../visit';
import { DomGenerator } from '../index';
import Block from '../Block';
import isDomNode from './shared/isDomNode';
import { Node } from '../../../interfaces';
import { State } from '../interfaces';
export default function visitEachBlock(
generator: DomGenerator,
block: Block,
state: State,
node: Node,
elementStack: Node[],
componentStack: Node[]
) {
const each = node.var;
const create_each_block = node._block.name;
const each_block_value = node._block.listName;
const iterations = node.iterations;
const params = block.params.join(', ');
const needsAnchor = node.next ? !isDomNode(node.next, generator) : !state.parentNode || !isDomNode(node.parent, generator);
const anchor = needsAnchor
? block.getUniqueName(`${each}_anchor`)
: (node.next && node.next.var) || 'null';
// hack the sourcemap, so that if data is missing the bug
// is easy to find
let c = node.start + 3;
while (generator.source[c] !== 'e') c += 1;
generator.code.overwrite(c, c + 4, 'length');
const length = `[✂${c}-${c+4}✂]`;
const mountOrIntro = node._block.hasIntroMethod ? 'i' : 'm';
const vars = {
each,
create_each_block,
each_block_value,
length,
iterations,
params,
anchor,
mountOrIntro,
};
block.contextualise(node.expression);
const { snippet } = node.metadata;
block.builders.init.addLine(`var ${each_block_value} = ${snippet};`);
if (node.key) {
keyed(generator, block, state, node, snippet, vars);
} else {
unkeyed(generator, block, state, node, snippet, vars);
}
const isToplevel = !state.parentNode;
if (needsAnchor) {
block.addElement(
anchor,
`@createComment()`,
`@createComment()`,
state.parentNode
);
}
if (node.else) {
const each_block_else = generator.getUniqueName(`${each}_else`);
block.builders.init.addLine(`var ${each_block_else} = null;`);
// TODO neaten this up... will end up with an empty line in the block
block.builders.init.addBlock(deindent`
if (!${each_block_value}.${length}) {
${each_block_else} = ${node.else._block.name}(${params}, #component);
${each_block_else}.c();
}
`);
block.builders.mount.addBlock(deindent`
if (${each_block_else}) {
${each_block_else}.${mountOrIntro}(${state.parentNode || '#target'}, null);
}
`);
const parentNode = state.parentNode || `${anchor}.parentNode`;
if (node.else._block.hasUpdateMethod) {
block.builders.update.addBlock(deindent`
if (!${each_block_value}.${length} && ${each_block_else}) {
${each_block_else}.p( changed, ${params} );
} else if (!${each_block_value}.${length}) {
${each_block_else} = ${node.else._block.name}(${params}, #component);
${each_block_else}.c();
${each_block_else}.${mountOrIntro}(${parentNode}, ${anchor});
} else if (${each_block_else}) {
${each_block_else}.u();
${each_block_else}.d();
${each_block_else} = null;
}
`);
} else {
block.builders.update.addBlock(deindent`
if (${each_block_value}.${length}) {
if (${each_block_else}) {
${each_block_else}.u();
${each_block_else}.d();
${each_block_else} = null;
}
} else if (!${each_block_else}) {
${each_block_else} = ${node.else._block.name}(${params}, #component);
${each_block_else}.c();
${each_block_else}.${mountOrIntro}(${parentNode}, ${anchor});
}
`);
}
block.builders.unmount.addLine(
`if (${each_block_else}) ${each_block_else}.u()`
);
block.builders.destroy.addBlock(deindent`
if (${each_block_else}) ${each_block_else}.d();
`);
}
node.children.forEach((child: Node) => {
visit(generator, node._block, node._state, child, elementStack, componentStack);
});
if (node.else) {
node.else.children.forEach((child: Node) => {
visit(generator, node.else._block, node.else._state, child, elementStack, componentStack);
});
}
}
function keyed(
generator: DomGenerator,
block: Block,
state: State,
node: Node,
snippet: string,
{
each,
create_each_block,
each_block_value,
length,
params,
anchor,
mountOrIntro,
}
) {
const key = block.getUniqueName('key');
const lookup = block.getUniqueName(`${each}_lookup`);
const iteration = block.getUniqueName(`${each}_iteration`);
const head = block.getUniqueName(`${each}_head`);
const last = block.getUniqueName(`${each}_last`);
const expected = block.getUniqueName(`${each}_expected`);
block.addVariable(lookup, `@blankObject()`);
block.addVariable(head);
block.addVariable(last);
if (node.children[0] && node.children[0].type === 'Element' && !generator.components.has(node.children[0].name)) {
// TODO or text/tag/raw
node._block.first = node.children[0]._state.parentNode; // TODO this is highly confusing
} else {
node._block.first = node._block.getUniqueName('first');
node._block.addElement(
node._block.first,
`@createComment()`,
`@createComment()`,
null
);
}
block.builders.init.addBlock(deindent`
for (var #i = 0; #i < ${each_block_value}.${length}; #i += 1) {
var ${key} = ${each_block_value}[#i].${node.key};
var ${iteration} = ${lookup}[${key}] = ${create_each_block}(${params}, ${each_block_value}, ${each_block_value}[#i], #i, #component, ${key});
if (${last}) ${last}.next = ${iteration};
${iteration}.last = ${last};
${last} = ${iteration};
if (#i === 0) ${head} = ${iteration};
}
`);
const targetNode = state.parentNode || '#target';
const anchorNode = state.parentNode ? 'null' : 'anchor';
block.builders.create.addBlock(deindent`
var ${iteration} = ${head};
while (${iteration}) {
${iteration}.c();
${iteration} = ${iteration}.next;
}
`);
block.builders.claim.addBlock(deindent`
var ${iteration} = ${head};
while (${iteration}) {
${iteration}.l(${state.parentNodes});
${iteration} = ${iteration}.next;
}
`);
block.builders.mount.addBlock(deindent`
var ${iteration} = ${head};
while (${iteration}) {
${iteration}.${mountOrIntro}(${targetNode}, ${anchorNode});
${iteration} = ${iteration}.next;
}
`);
const dynamic = node._block.hasUpdateMethod;
const parentNode = isDomNode(node.parent, generator) ? node.parent.var : `${anchor}.parentNode`;
let destroy;
if (node._block.hasOutroMethod) {
const fn = block.getUniqueName(`${each}_outro`);
block.builders.init.addBlock(deindent`
function ${fn}(iteration) {
iteration.o(function() {
iteration.u();
iteration.d();
${lookup}[iteration.key] = null;
});
}
`);
destroy = deindent`
while (${expected}) {
${fn}(${expected});
${expected} = ${expected}.next;
}
for (#i = 0; #i < discard_pile.length; #i += 1) {
if (discard_pile[#i].discard) {
${fn}(discard_pile[#i]);
}
}
`;
} else {
const fn = block.getUniqueName(`${each}_destroy`);
block.builders.init.addBlock(deindent`
function ${fn}(iteration) {
iteration.u();
iteration.d();
${lookup}[iteration.key] = null;
}
`);
destroy = deindent`
while (${expected}) {
${fn}(${expected});
${expected} = ${expected}.next;
}
for (#i = 0; #i < discard_pile.length; #i += 1) {
var ${iteration} = discard_pile[#i];
if (${iteration}.discard) {
${fn}(${iteration});
}
}
`;
}
block.builders.update.addBlock(deindent`
var ${each_block_value} = ${snippet};
var ${expected} = ${head};
var ${last} = null;
var discard_pile = [];
for (#i = 0; #i < ${each_block_value}.${length}; #i += 1) {
var ${key} = ${each_block_value}[#i].${node.key};
var ${iteration} = ${lookup}[${key}];
${dynamic &&
`if (${iteration}) ${iteration}.p(changed, ${params}, ${each_block_value}, ${each_block_value}[#i], #i);`}
if (${expected}) {
if (${key} === ${expected}.key) {
${expected} = ${expected}.next;
} else {
if (${iteration}) {
// probably a deletion
while (${expected} && ${expected}.key !== ${key}) {
${expected}.discard = true;
discard_pile.push(${expected});
${expected} = ${expected}.next;
};
${expected} = ${expected} && ${expected}.next;
${iteration}.discard = false;
${iteration}.last = ${last};
if (!${expected}) ${iteration}.m(${parentNode}, ${anchor});
} else {
// key is being inserted
${iteration} = ${lookup}[${key}] = ${create_each_block}(${params}, ${each_block_value}, ${each_block_value}[#i], #i, #component, ${key});
${iteration}.c();
${iteration}.${mountOrIntro}(${parentNode}, ${expected}.first);
${expected}.last = ${iteration};
${iteration}.next = ${expected};
}
}
} else {
// we're appending from this point forward
if (${iteration}) {
${iteration}.discard = false;
${iteration}.next = null;
${iteration}.m(${parentNode}, ${anchor});
} else {
${iteration} = ${lookup}[${key}] = ${create_each_block}(${params}, ${each_block_value}, ${each_block_value}[#i], #i, #component, ${key});
${iteration}.c();
${iteration}.${mountOrIntro}(${parentNode}, ${anchor});
}
}
if (${last}) ${last}.next = ${iteration};
${iteration}.last = ${last};
${node._block.hasIntroMethod && `${iteration}.i(${parentNode}, ${anchor});`}
${last} = ${iteration};
}
if (${last}) ${last}.next = null;
${destroy}
${head} = ${lookup}[${each_block_value}[0] && ${each_block_value}[0].${node.key}];
`);
if (!state.parentNode) {
block.builders.unmount.addBlock(deindent`
var ${iteration} = ${head};
while (${iteration}) {
${iteration}.u();
${iteration} = ${iteration}.next;
}
`);
}
block.builders.destroy.addBlock(deindent`
var ${iteration} = ${head};
while (${iteration}) {
${iteration}.d();
${iteration} = ${iteration}.next;
}
`);
}
function unkeyed(
generator: DomGenerator,
block: Block,
state: State,
node: Node,
snippet: string,
{
create_each_block,
each_block_value,
length,
iterations,
params,
anchor,
mountOrIntro,
}
) {
block.builders.init.addBlock(deindent`
var ${iterations} = [];
for (var #i = 0; #i < ${each_block_value}.${length}; #i += 1) {
${iterations}[#i] = ${create_each_block}(${params}, ${each_block_value}, ${each_block_value}[#i], #i, #component);
}
`);
const targetNode = state.parentNode || '#target';
const anchorNode = state.parentNode ? 'null' : 'anchor';
block.builders.create.addBlock(deindent`
for (var #i = 0; #i < ${iterations}.length; #i += 1) {
${iterations}[#i].c();
}
`);
block.builders.claim.addBlock(deindent`
for (var #i = 0; #i < ${iterations}.length; #i += 1) {
${iterations}[#i].l(${state.parentNodes});
}
`);
block.builders.mount.addBlock(deindent`
for (var #i = 0; #i < ${iterations}.length; #i += 1) {
${iterations}[#i].${mountOrIntro}(${targetNode}, ${anchorNode});
}
`);
const allDependencies = new Set(node._block.dependencies);
const { dependencies } = node.metadata;
dependencies.forEach((dependency: string) => {
allDependencies.add(dependency);
});
// TODO do this for keyed blocks as well
const condition = Array.from(allDependencies)
.map(dependency => `changed.${dependency}`)
.join(' || ');
const parentNode = isDomNode(node.parent, generator) ? node.parent.var : `${anchor}.parentNode`;
if (condition !== '') {
const forLoopBody = node._block.hasUpdateMethod
? node._block.hasIntroMethod
? deindent`
if (${iterations}[#i]) {
${iterations}[#i].p(changed, ${params}, ${each_block_value}, ${each_block_value}[#i], #i);
} else {
${iterations}[#i] = ${create_each_block}(${params}, ${each_block_value}, ${each_block_value}[#i], #i, #component);
${iterations}[#i].c();
}
${iterations}[#i].i(${parentNode}, ${anchor});
`
: deindent`
if (${iterations}[#i]) {
${iterations}[#i].p(changed, ${params}, ${each_block_value}, ${each_block_value}[#i], #i);
} else {
${iterations}[#i] = ${create_each_block}(${params}, ${each_block_value}, ${each_block_value}[#i], #i, #component);
${iterations}[#i].c();
${iterations}[#i].m(${parentNode}, ${anchor});
}
`
: deindent`
${iterations}[#i] = ${create_each_block}(${params}, ${each_block_value}, ${each_block_value}[#i], #i, #component);
${iterations}[#i].c();
${iterations}[#i].${mountOrIntro}(${parentNode}, ${anchor});
`;
const start = node._block.hasUpdateMethod ? '0' : `${iterations}.length`;
const outro = block.getUniqueName('outro');
const destroy = node._block.hasOutroMethod
? deindent`
function ${outro}(i) {
if (${iterations}[i]) {
${iterations}[i].o(function() {
${iterations}[i].u();
${iterations}[i].d();
${iterations}[i] = null;
});
}
}
for (; #i < ${iterations}.length; #i += 1) ${outro}(#i);
`
: deindent`
for (; #i < ${iterations}.length; #i += 1) {
${iterations}[#i].u();
${iterations}[#i].d();
}
${iterations}.length = ${each_block_value}.${length};
`;
block.builders.update.addBlock(deindent`
var ${each_block_value} = ${snippet};
if (${condition}) {
for (var #i = ${start}; #i < ${each_block_value}.${length}; #i += 1) {
${forLoopBody}
}
${destroy}
}
`);
}
block.builders.unmount.addBlock(deindent`
for (var #i = 0; #i < ${iterations}.length; #i += 1) {
${iterations}[#i].u();
}
`);
block.builders.destroy.addBlock(`@destroyEach(${iterations});`);
}