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svelte/src/compile/nodes/shared/Expression.ts

503 lines
13 KiB

import Component from '../../Component';
import { walk } from 'estree-walker';
import isReference from 'is-reference';
import flattenReference from '../../../utils/flattenReference';
import { createScopes, Scope, extractNames } from '../../../utils/annotateWithScopes';
import { Node } from '../../../interfaces';
import globalWhitelist from '../../../utils/globalWhitelist';
import deindent from '../../../utils/deindent';
import Wrapper from '../../render-dom/wrappers/shared/Wrapper';
import sanitize from '../../../utils/sanitize';
import TemplateScope from './TemplateScope';
import getObject from '../../../utils/getObject';
import { nodes_match } from '../../../utils/nodes_match';
import Block from '../../render-dom/Block';
const binaryOperators: Record<string, number> = {
'**': 15,
'*': 14,
'/': 14,
'%': 14,
'+': 13,
'-': 13,
'<<': 12,
'>>': 12,
'>>>': 12,
'<': 11,
'<=': 11,
'>': 11,
'>=': 11,
'in': 11,
'instanceof': 11,
'==': 10,
'!=': 10,
'===': 10,
'!==': 10,
'&': 9,
'^': 8,
'|': 7
};
const logicalOperators: Record<string, number> = {
'&&': 6,
'||': 5
};
const precedence: Record<string, (node?: Node) => number> = {
Literal: () => 21,
Identifier: () => 21,
ParenthesizedExpression: () => 20,
MemberExpression: () => 19,
NewExpression: () => 19, // can be 18 (if no args) but makes no practical difference
CallExpression: () => 19,
UpdateExpression: () => 17,
UnaryExpression: () => 16,
BinaryExpression: (node: Node) => binaryOperators[node.operator],
LogicalExpression: (node: Node) => logicalOperators[node.operator],
ConditionalExpression: () => 4,
AssignmentExpression: () => 3,
YieldExpression: () => 2,
SpreadElement: () => 1,
SequenceExpression: () => 0
};
export default class Expression {
type = 'Expression';
component: Component;
owner: Wrapper;
node: any;
snippet: string;
references: Set<string>;
dependencies: Set<string> = new Set();
contextual_dependencies: Set<string> = new Set();
template_scope: TemplateScope;
scope: Scope;
scope_map: WeakMap<Node, Scope>;
is_synthetic: boolean;
declarations: string[] = [];
usesContext = false;
usesEvent = false;
rendered: string;
constructor(component: Component, owner: Wrapper, template_scope: TemplateScope, info) {
// TODO revert to direct property access in prod?
Object.defineProperties(this, {
component: {
value: component
}
});
this.node = info;
this.template_scope = template_scope;
this.owner = owner;
this.is_synthetic = owner.isSynthetic;
const { dependencies, contextual_dependencies } = this;
let { map, scope } = createScopes(info);
this.scope = scope;
this.scope_map = map;
const expression = this;
let function_expression;
// discover dependencies, but don't change the code yet
walk(info, {
enter(node: any, parent: any, key: string) {
// don't manipulate shorthand props twice
if (key === 'value' && parent.shorthand) return;
if (map.has(node)) {
scope = map.get(node);
}
if (!function_expression && /FunctionExpression/.test(node.type)) {
function_expression = node;
}
if (isReference(node, parent)) {
const { name, nodes } = flattenReference(node);
if (scope.has(name)) return;
if (globalWhitelist.has(name) && !component.var_lookup.has(name)) return;
if (name[0] === '$' && template_scope.names.has(name.slice(1))) {
component.error(node, {
code: `contextual-store`,
message: `Stores must be declared at the top level of the component (this may change in a future version of Svelte)`
});
}
if (template_scope.is_let(name)) {
if (!function_expression) {
dependencies.add(name);
}
} else if (template_scope.names.has(name)) {
expression.usesContext = true;
contextual_dependencies.add(name);
if (!function_expression) {
template_scope.dependenciesForName.get(name).forEach(name => dependencies.add(name));
}
} else {
if (!function_expression) {
dependencies.add(name);
}
component.add_reference(name);
component.warn_if_undefined(nodes[0], template_scope);
}
this.skip();
}
// track any assignments from template expressions as mutable
let names;
let deep = false;
if (function_expression) {
if (node.type === 'AssignmentExpression') {
deep = node.left.type === 'MemberExpression';
names = deep
? [getObject(node.left).name]
: extractNames(node.left);
} else if (node.type === 'UpdateExpression') {
const { name } = getObject(node.argument);
names = [name];
}
}
if (names) {
names.forEach(name => {
if (template_scope.names.has(name)) {
template_scope.dependenciesForName.get(name).forEach(name => {
const variable = component.var_lookup.get(name);
if (variable) variable[deep ? 'mutated' : 'reassigned'] = true;
});
} else {
component.add_reference(name);
const variable = component.var_lookup.get(name);
if (variable) variable[deep ? 'mutated' : 'reassigned'] = true;
}
});
}
},
leave(node) {
if (map.has(node)) {
scope = scope.parent;
}
if (node === function_expression) {
function_expression = null;
}
}
});
}
dynamic_dependencies() {
return Array.from(this.dependencies).filter(name => {
if (this.template_scope.is_let(name)) return true;
if (name === '$$props') return true;
const variable = this.component.var_lookup.get(name);
if (!variable) return false;
if (variable.mutated || variable.reassigned) return true; // dynamic internal state
if (!variable.module && variable.writable && variable.export_name) return true; // writable props
});
}
getPrecedence() {
return this.node.type in precedence ? precedence[this.node.type](this.node) : 0;
}
// TODO move this into a render-dom wrapper?
render(block: Block) {
if (this.rendered) return this.rendered;
const {
component,
declarations,
scope_map: map,
template_scope,
owner,
is_synthetic
} = this;
let scope = this.scope;
const { code } = component;
let function_expression;
let pending_assignments = new Set();
let dependencies: Set<string>;
let contextual_dependencies: Set<string>;
// rewrite code as appropriate
walk(this.node, {
enter(node: any, parent: any, key: string) {
// don't manipulate shorthand props twice
if (key === 'value' && parent.shorthand) return;
code.addSourcemapLocation(node.start);
code.addSourcemapLocation(node.end);
if (map.has(node)) {
scope = map.get(node);
}
if (isReference(node, parent)) {
const { name, nodes } = flattenReference(node);
if (scope.has(name)) return;
if (globalWhitelist.has(name) && !component.var_lookup.has(name)) return;
if (function_expression) {
if (template_scope.names.has(name)) {
contextual_dependencies.add(name);
template_scope.dependenciesForName.get(name).forEach(dependency => {
dependencies.add(dependency);
});
} else {
dependencies.add(name);
component.add_reference(name);
}
} else if (!is_synthetic && isContextual(component, template_scope, name)) {
code.prependRight(node.start, key === 'key' && parent.shorthand
? `${name}: ctx.`
: 'ctx.');
}
if (node.type === 'MemberExpression') {
nodes.forEach(node => {
code.addSourcemapLocation(node.start);
code.addSourcemapLocation(node.end);
});
}
this.skip();
}
if (function_expression) {
if (node.type === 'AssignmentExpression') {
const names = node.left.type === 'MemberExpression'
? [getObject(node.left).name]
: extractNames(node.left);
if (node.operator === '=' && nodes_match(node.left, node.right)) {
const dirty = names.filter(name => {
return !scope.declarations.has(name);
});
if (dirty.length) component.has_reactive_assignments = true;
code.overwrite(node.start, node.end, dirty.map(n => component.invalidate(n)).join('; '));
} else {
names.forEach(name => {
if (scope.declarations.has(name)) return;
const variable = component.var_lookup.get(name);
if (variable && variable.hoistable) return;
pending_assignments.add(name);
});
}
} else if (node.type === 'UpdateExpression') {
const { name } = getObject(node.argument);
if (scope.declarations.has(name)) return;
const variable = component.var_lookup.get(name);
if (variable && variable.hoistable) return;
pending_assignments.add(name);
}
} else {
if (node.type === 'AssignmentExpression') {
// TODO should this be a warning/error? `<p>{foo = 1}</p>`
}
if (node.type === 'FunctionExpression' || node.type === 'ArrowFunctionExpression') {
function_expression = node;
dependencies = new Set();
contextual_dependencies = new Set();
}
}
},
leave(node: Node, parent: Node) {
if (map.has(node)) scope = scope.parent;
if (node === function_expression) {
if (pending_assignments.size > 0) {
if (node.type !== 'ArrowFunctionExpression') {
// this should never happen!
throw new Error(`Well that's odd`);
}
// TOOD optimisation — if this is an event handler,
// the return value doesn't matter
}
const name = component.getUniqueName(
sanitize(get_function_name(node, owner))
);
const args = contextual_dependencies.size > 0
? [`{ ${Array.from(contextual_dependencies).join(', ')} }`]
: [];
let original_params;
if (node.params.length > 0) {
original_params = code.slice(node.params[0].start, node.params[node.params.length - 1].end);
args.push(original_params);
}
let body = code.slice(node.body.start, node.body.end).trim();
if (node.body.type !== 'BlockStatement') {
if (pending_assignments.size > 0) {
const insert = Array.from(pending_assignments).map(name => component.invalidate(name)).join('; ');
pending_assignments = new Set();
component.has_reactive_assignments = true;
body = deindent`
{
const $$result = ${body};
${insert};
return $$result;
}
`;
} else {
body = `{\n\treturn ${body};\n}`;
}
}
const fn = deindent`
function ${name}(${args.join(', ')}) ${body}
`;
if (dependencies.size === 0 && contextual_dependencies.size === 0) {
// we can hoist this out of the component completely
component.fully_hoisted.push(fn);
code.overwrite(node.start, node.end, name);
component.add_var({
name,
internal: true,
hoistable: true,
referenced: true
});
}
else if (contextual_dependencies.size === 0) {
// function can be hoisted inside the component init
component.partly_hoisted.push(fn);
code.overwrite(node.start, node.end, `ctx.${name}`);
component.add_var({
name,
internal: true,
referenced: true
});
}
else {
// we need a combo block/init recipe
component.partly_hoisted.push(fn);
code.overwrite(node.start, node.end, name);
component.add_var({
name,
internal: true,
referenced: true
});
declarations.push(deindent`
function ${name}(${original_params ? '...args' : ''}) {
return ctx.${name}(ctx${original_params ? ', ...args' : ''});
}
`);
}
function_expression = null;
dependencies = null;
contextual_dependencies = null;
}
if (/Statement/.test(node.type)) {
if (pending_assignments.size > 0) {
const has_semi = code.original[node.end - 1] === ';';
const insert = (
(has_semi ? ' ' : '; ') +
Array.from(pending_assignments).map(name => component.invalidate(name)).join('; ')
);
if (/^(Break|Continue|Return)Statement/.test(node.type)) {
if (node.argument) {
code.overwrite(node.start, node.argument.start, `var $$result = `);
code.appendLeft(node.argument.end, `${insert}; return $$result`);
} else {
code.prependRight(node.start, `${insert}; `);
}
} else if (parent && /(If|For(In|Of)?|While)Statement/.test(parent.type) && node.type !== 'BlockStatement') {
code.prependRight(node.start, '{ ');
code.appendLeft(node.end, `${insert}; }`);
} else {
code.appendLeft(node.end, `${insert};`);
}
component.has_reactive_assignments = true;
pending_assignments = new Set();
}
}
}
});
if (declarations.length > 0) {
block.maintainContext = true;
declarations.forEach(declaration => {
block.builders.init.addBlock(declaration);
});
}
return this.rendered = `[✂${this.node.start}-${this.node.end}✂]`;
}
}
function get_function_name(node, parent) {
if (parent.type === 'EventHandler') {
return `${parent.name}_handler`;
}
if (parent.type === 'Action') {
return `${parent.name}_function`;
}
return 'func';
}
function isContextual(component: Component, scope: TemplateScope, name: string) {
if (name === '$$props') return true;
// if it's a name below root scope, it's contextual
if (!scope.isTopLevel(name)) return true;
const variable = component.var_lookup.get(name);
// hoistables, module declarations, and imports are non-contextual
if (!variable || variable.hoistable) return false;
// assume contextual
return true;
}